Elevating Excellence in UV-Vis Analyses - Spectroscopy

Elevating Excellence 

in UV-Vis Analyses 

5L^YLZLHYJONYHKL 

Z`Z[LTZV\[JSHZZ 

[OLJVTWL[P[PVU 

.L[[OLZJVVWVU7HNL 

VY]PZP[^^^ZZPZOPTHKa\JVT

® 

September 2011 Volume 26 Number 9 

www.spectroscopyonline.com 

Surface-Enhanced 

Resonant Raman Scattering 

and Ink Analysis 

Ion Lifetimes in MS 

Measurement Techniques for Mercury 

ICP-OES for Elemental Analysis

You are 

prepared 

Through continual investment in AA, ICP and ICP-MS technology, we are 

dedicated to providing the most cost effective, productive and flexible solutions. 

From the widest range of trace elemental instruments you can choose 

the most cost effective package to easily analyze diverse samples precisely 

and consistently. For your sustainable success, partner with the experienced 

supplier of trace elemental solutions. 

for every challenge in 

trace elemental analysis 

• www.thermoscientific.com/prepared 

iCE 3000 Series AA 

Innovative design for ease of 

use with flame and furnace AA 

technology 

iCAP 6000 Series ICP-OES 

Reliable, routine multi-element 

analysis with the best performing 

ICP-OES 

© 2011 Thermo Fisher Scientific Inc. All rights reserved. 

XSERIES 2 ICP-MS 

Ultimate performance with high 

throughput 

ELEMENT 2 HR-ICP-MS 

High resolution ICP-MS for the 

most demanding of applications

the 

REMARKABLY BETTER 

ATOMIC 

SPECTROSCOPY 

RUNS 

revolution 

on AIR 

Introducing the NEW Agilent 4100 MP-AES. Say goodbye to 

fl ammable and expensive gases. Say hello to enhanced productivity. 

The Agilent 4100 Microwave Plasma-Atomic Emission Spectrometer runs 

entirely on air. It’s safer and more cost effi cient. It enables superior detection 

and unattended multi-element analysis. It’s the most signifi cant advancement 

in atomic spectroscopy in decades. In other words: It’s time to run on air. 

JOIN THE REVOLUTION. Learn more about the NEW Agilent 4100 MP-AES. 

www.agilent.com/chem/RunsOnAir 

© Agilent Technologies, Inc. 2011

te 

4 Spectroscopy 26(9) September 2011 


® 

Chemical 

imaging just 

got faster! 

1mm 

Raman image of 

a pharmaceutical 

tablet 

MANUSCRIPTS: To discuss possible article topics or obtain manuscript preparation 

guidelines, contact the editorial director at: (732) 346-3020, e-mail: lbush@advanstar.com. 

Publishers assume no responsibility for safety of artwork, photographs, or manuscripts. 

Every caution is taken to ensure accuracy, but publishers cannot accept responsibility for the 

information supplied herein or for any opinion expressed. 

SUBSCRIPTIONS: For subscription information: Spectroscopy, P.O. Box 6196, Duluth, MN 

55806-6196; (877) 527-7008, 7:00 a.m. to 6:00 p.m. CST. Outside the U.S., +1-218-740-6477. 

Delivery of Spectroscopy outside the U.S. is 3–14 days after printing. Single-copy price: 

U.S., $10.00 + $7.00 postage and handling ($17.00 total); Canada and Mexico, $12.00 + $7.00 

postage and handling ($19.00 total); Other international, $15.00 + $7.00 postage and handling 

($22.00 total). 

CHANGE OF ADDRESS: Send change of address to Spectroscopy, P.O. Box 6196, Duluth, MN 

55806-6196; provide old mailing label as well as new address; include ZIP or postal code. 

Allow 4–6 weeks for change. Alternately, go to the following URL for address changes or 

subscription renewal: https://advanstar.replycentral.com/?PID=581 

RETURN ALL UNDELIVERABLE CANADIAN ADDRESSES TO: Pitney Bowes, P.O. Box 

25542, London, ON N6C 6B2, CANADA. PUBLICATIONS MAIL AGREEMENT No.40612608. 

REPRINTS: Reprints of all articles in this issue and past issues are available 

(500 minimum). Call 800-290-5460, x100 or e-mail AdvanstarReprints@theYGSgroup.com. 

DIRECT LIST RENTAL: Contact Tamara Phillips, (440) 891-2773; e-mail: tphillips@ 

advanstar.com 

INTERNATIONAL LICENSING: Maureen Cannon, (440) 891-2742, 

fax: (440) 891-2650; e-mail: mcannon@advanstar.com. 

30 minutes 

50% Recycled Paper 

s10-20% Post Consumer Wa 

Red: caffeine 

Green: aspirin 

Blue: paracetamol 

Renishaw’s StreamLine fast chemical 

imaging system 

Renishaw’s new StreamLine technology enables 

you to produce Raman chemical images far faster 

than has been possible before. Raman images that 

used to take hours to produce can now be created 

in minutes. 

StreamLine technology is available as an option 

for Renishaw’s inVia Raman microscopes. It 

comprises proprietary hardware and software that 

dramatically increase the speed of data acquisition. 

Call us now to find out more. 

Apply innovation. 

©2011 Advanstar Communications Inc. All rights reserved. No part of this publication may 

be reproduced or transmitted in any form or by any means, electronic or mechanical including 

by photocopy, recording, or information storage and retrieval without permission in writing 

from the publisher. Authorization to photocopy items for internal/educational or personal use, 

or the internal/educational or personal use of specific clients is granted by Advanstar Communications 

Inc. for libraries and other users registered with the Copyright Clearance Center, 222 

Rosewood Dr. Danvers, MA 01923, 978-750-8400 fax 978-646-8700 or visit http://www. 

copyright.com online. For uses beyond those listed above, please direct your written request 

to Permission Dept. fax 440-756-5255 or email: mcannon@advanstar.com. 

Advanstar Communications Inc. provides certain customer contact data (such as customers’ 

names, addresses, phone numbers, and e-mail addresses) to third parties who wish to promote 

relevant products, services, and other opportunities that may be of interest to you. If you do not 

want Advanstar Communications Inc. to make your contact information available to third parties 

for marketing purposes, simply call toll-free 866-529-2922 between the hours of 7:30 a.m. and 

5 p.m. CST and a customer service representative will assist you in removing your name from 

Advanstar’s lists. Outside the U.S., please phone 218-740-6477. 

Spectroscopy does not verify any claims or other information appearing in any of the advertisements 

contained in the publication, and cannot take responsibility for any losses or other 

damages incurred by readers in reliance of such content. 

Spectroscopy welcomes unsolicited articles, manuscripts, photographs, illustrations and 

other materials but cannot be held responsible for their safekeeping or return. 

To subscribe, call toll-free 877-527-7008. Outside the U.S. call 218-740-6477. 

Renishaw Inc. 5277 Trillium Boulevard, Hoffman Estates, IL 60192 

T 847 286 9953 F 847 286 9974 E usa@renishaw.com 

www.renishaw.com/raman 

Advanstar Communications Inc. (www.advanstar.com) is a leading worldwide media company 

providing integrated marketing solutions for the Fashion, Life Sciences and Powersports 

industries. Advanstar serves business professionals and consumers in these industries with its 

portfolio of 91 events, 67 publications and directories, 150 electronic publications and Web 

sites, as well as educational and direct marketing products and services. Market leading brands 

and a commitment to delivering innovative, quality products and services enables Advanstar 

to “Connect Our Customers With Theirs.” Advanstar has approximately 1000 employees and 

currently operates from multiple offices in North America and Europe.

DISTINCTLY 

BETTER 

MOLECULAR SPEC 

Agilent’s Cary portfolio is the molecular spectroscopy leader. 

Highest precision. Fastest performance. Best results. All thanks to a portfolio 

of UV-Vis-NIR, FTIR, and Fluorescence instruments that deliver reliable, precise, 

and reproducible results—fast. Our proven record of optical design excellence 

and innovation ensures you get the right answer every time. That’s leadership 

you can count on. That’s Distinctly Better. 

© Agilent Technologies, Inc. 2011 

To learn more about Agilent’s Cary Molecular Spectroscopy portfolio, visit 

www.agilent.com/chem/molecular


® 

CONTENTS 


Volume 26 Number 9 

SEPTEMBER 2011 

September 2011 

Volume 26 Number 9 

Columns 

MASS SPECTROMETRY FORUM 12 

September 2011 Volume 26 Number 9 


® 

Consequences of Finite Ion Lifetimes in Mass Spectrometry 

As we construct more-complex instruments that process packets of ions in 

time and space, the issue of ion lifetimes is becoming more important. 

Kenneth L. Busch 

THE BASELINE 

18 

Surface-Enhanced 

Resonant Raman Scattering 

and Ink Analysis 

Ion Lifetimes in MS 

Measurement Techniques for Mercury 

ICP-OES for Elemental Analysis 

Cover image courtesy of 

Getty Images/Chad Baker 

Maxwell’s Equations, Part III 

Here’s the fundamental calculus you need to understand Maxwell’s first equation. 

David W. Ball 

Periodic Reviews of Computerized Systems, Part I 

Annex 11 to the EU’s updated GMP regulations calls for periodic re-evaluation of 

computerized systems. This is what you need to know about the new rules. 

R.D. McDowall 

FOCUS ON QUALITY 

28 

ON THE WEB 

ATOMIC PERSPECTIVES 

40 

ON DEMAND WEB SEMINARS 

Pharmaceutical Surveillance with 

Multiple Distributed Portable 

Raman Spectrometers 

John Kauffman and Connie Ruzicka, 

Division of Pharmaceutical Analysis, 

U.S. Food and Drug Administration 

A Compound-Based Approach to 

Simplify Method Development and 

Data Processing for Multiple Residue 

Analysis by GC–MS-MS 

Jim Koers and Kefei Wang, 

Bruker Daltonics 

Problem Solving with 

Energy Dispersive Micro-XRF 

Bruce Scruggs and Andreas Wittkopp, Edax 

SPECTROSCOPY SPOTLIGHT 

Analyzing Nanomaterials with Raman 

Mircea Chipara of the University of Texas- 

Pan American on using Raman to analyze 

carbonaceous nanomaterials. 

TECHNOLOGY FORUM 

The Future of Atomic Absorption 

Many laboratories are still finding room for 

innovation with this mature technique. 

Join the 

Spectroscopy Group 

on LinkedIn 

Measurement Techniques for Mercury: Which Approach Is 

Right for You? 

The advantages and disadvantages of measuring mercury with cold vapor atomic absorption 

spectroscopy, cold vapor atomic fluorescence spectroscopy, and direct analysis by thermal 

decomposition are explained. 

David Pfeil 

Articles 

Spectrometers for Elemental Spectrochemical Analysis, Part IV: 

Inductively Coupled Plasma Optical Emission Spectrometers 44 

A tutorial on inductively coupled plasma (ICP) excitation and sample introduction systems. 

Carlos Augusto Coutinho and Volker Thomsen 

DEPARTMENTS 

News Spectrum . . . . . . 10 Product Resources . . . . 54 Ad Index . . . . . . . . . . . . 58 

Spectroscopy (ISSN 0887-6703 [print], ISSN 1939-1900 [digital]) is published monthly by Advanstar Communications, Inc., 

131 West First Street, Duluth, MN 55802-2065. Spectroscopy is distributed free of charge to users and specifiers of spectroscopic 

equipment in the United States. Spectroscopy is available on a paid subscription basis to nonqualified readers at the rate of: 

U.S. and possessions: 1 year (12 issues), $74.95; 2 years (24 issues), $134.50. Canada/Mexico: 1 year, $95; 2 years, $150. International: 

1 year (12 issues), $140; 2 years (24 issues), $250. Periodicals postage paid at Duluth, MN 55806 and at additional mailing 

offices. POSTMASTER: Send address changes to Spectroscopy, P.O. Box 6196, Duluth, MN 55806-6196. PUBLICATIONS MAIL 

AGREEMENT NO. 40612608, Return Undeliverable Canadian Addresses to: Pitney Bowes, P. O. Box 25542, London, ON N6C 

6B2, CANADA. Canadian GST number: R-124213133RT001. Printed in the U.S.A.

www.ssi.shimadzu.com 

Elevating Excellence in UV-Vis Analyses 

From Performance to Price, New Compact, Research-Grade 

UV-Vis Spectrophotometers Outclass the Competition 

With advanced optical systems engineered to 

substantially reduce stray light, Shimadzu’s 

new ultra-compact single-monochromator UV- 

2600 and double monochromator UV-2700 

spectrophotometers offer a number of highperformance 

and productivity-enhancing features 

to enable confident and convenient use for 

routine analysis as well as demanding research 

applications. At prices that can’t be beat. 

Shimadzu’s UV-2600/2700 

spectrophotometers feature: 

n 

n 

n 

n 

n 

n 

n 

High absorbance level to 8 Abs 

Wide measurement range to 1400 nm 

Ultra low stray light (0.00005 %T at 220 nm) 

Smallest footprint in their class 

USB connection 

Wide range of accessories and 

software packages available 

Unbelievable performance/price ratio 

For pharmaceutical and 

other applications requiring 

that hardware be validated, 

the UV-2600/2700 Series 

provides validation software 

as standard. 

You have demands. Shimadzu delivers. 

Learn more about Shimadzu’s UV-2600/2700. 

Call (800) 477-1227 or visit us online at 

www.ssi.shimadzu.com/262700 

SHIMADZU UV-2600/UV-2700 

Order consumables and accessories on-line at http://store.shimadzu.com 

Shimadzu Scientific Instruments Inc., 7102 Riverwood Dr., Columbia, MD 21046, USA



® 

PUBLISHING & SALES 

485F US Highway One South, Suite 100, Iselin, NJ 08830 

(732) 596-0276, Fax: (732) 647-1235 

Michael J. Tessalone 

Science Group Publisher, mtessalone@advanstar.com 

Edward Fantuzzi 

Publisher, efantuzzi@advanstar.com 

Stephanie Shaffer 

East Coast Sales Manager, sshaffer@advanstar.com 

(508) 481-5885 

EDITORIAL 

Laura Bush 

Editorial Director, lbush@advanstar.com 

Megan Evans 

Managing Editor, mevans@advanstar.com 

Stephen A. Brown 

Group Technical Editor, sbrown@advanstar.com 

Cindy Delonas 

Associate Editor, cdelonas@advanstar.com 

Dan Ward 

Art Director, dward@media.advanstar.com 

MARKETING 

Anne Young 

Marketing Manager, ayoung@advanstar.com 

MARKET DEvELOPMENT 

Tamara Phillips 

Direct List Rentals, tphillips@advanstar.com 

YGS Group 

Reprints, advanstarreprints@theYGSgroup.com 

Maureen Cannon 

Permissions, mcannon@advanstar.com 

PRODUCTION AND AUDIENCE DEvELOPMENT 

David Erickson 

Production Manager, derickson@media.advanstar.com 

Peggy Olson 

Audience Development Manager, polson@advanstar.com 

Gail Mantay 

Audience Development Assistant Manager, gmantay@advanstar.com 

Joseph Loggia 

President, Chief Executive Officer 

Theodore S. Alpert 

Executive Vice-President, Finance & Chief Financial Officer 

Tony Calanca 

Executive Vice-President, Exhibitions 

Georgiann DeCenzo 

Executive Vice-President, Licensing, Market Development & Europe 

Chris DeMoulin 

Executive Vice-President, Fashion & President MAGIC International 

Thomas Ehardt 

Executive Vice-President, Chief Administrative Officer 

Eric I. Lisman 

Executive Vice-President, Corporate Development 

Daniel Phillips 

Executive Vice-President, Powersports, Dental & Veterinary 

Andrew Pollard 

Executive Vice-President, Fashion & President, PROJECT 

Steve Sturm 

Executive Vice-President, Chief Marketing Officer 

Ron Wall 

Executive Vice-President, Pharmaceutical/Science & CBI 

Francis Heid 

Vice-President, Media Operations 

J vaughn 

Vice-President, Information Technology 

Mike Alic 

Vice-President, Electronic Media Group 

Nancy Nugent 

Vice-President, Human Resources 

Ward D. Hewins 

Vice-President, General Counsel 

David C. Esola 

Vice-President, General Manager 

Peter Houston 

Director of Content

www.spectroscopyonline.com September 2011 Spectroscopy 26(9) 9 

Editorial Advisory Board 

Ramon M. Barnes University of Massachusetts 

Paul N. Bourassa Lifeblood 

Deborah Bradshaw Consultant 

Kenneth L. Busch Wyvern Associates 

Ashok L. Cholli University of Massachusetts at Lowell 

David M. Coleman Wayne State University 

Bruce Hudson Syracuse University 

Kathryn S. Kalasinsky Armed Forces Institute of Pathology 

David Lankin University of Illinois at Chicago, College of Pharmacy 

Barbara S. Larsen DuPont Central Research and Development 

Ian R. Lewis Kaiser Optical Systems 

Jeffrey Hirsch Thermo Fisher Scientific 

Howard Mark Mark Electronics 

R.D. McDowall McDowall Consulting 

Linda Baine McGown Rensselaer Polytechnic Institute 

Robert G. Messerschmidt Rare Light, Inc. 

Francis M. Mirabella Jr. Equistar Technology Center 

John Monti Shimadzu Scientific Instruments 

Thomas M. Niemczyk University of New Mexico 

Anthony J. Nip CambridgeSoft Corp. 

John W. Olesik The Ohio State University 

Richard J. Saykally University of California, Berkeley 

Jerome Workman Jr. Consultant 

Contributing Editors: 

Fran Adar Horiba Jobin Yvon 

David W. Ball Cleveland State University 

Kenneth L. Busch Wyvern Associates 

Howard Mark Mark Electronics 

Volker Thomsen Consultant 

Jerome Workman Jr. Consultant 

Process Analysis Advisory Panel: 

James M. Brown Exxon Research and Engineering Company 

Bruce Buchanan Sensors-2-Information 

Lloyd W. Burgess CPAC, University of Washington 

James Rydzak Glaxo SmithKline 

Robert E. Sherman CIRCOR Instrumentation Technologies 

John Steichen DuPont Central Research and Development 

D. Warren Vidrine Vidrine Consulting 

European Regional Editors: 

John M. Chalmers VSConsulting, United Kingdom 

David A.C. Compton Industrial Chemicals Ltd. 

Spectroscopy’s Editorial Advisory Board is a group of distinguished individuals 

assembled to help the publication fulfill its editorial mission to promote the effective 

use of spectroscopic technology as a practical research and measurement tool. 

With recognized expertise in a wide range of technique and application areas, board 

members perform a range of functions, such as reviewing manuscripts, suggesting 

authors and topics for coverage, and providing the editor with general direction and 

feedback. We are indebted to these scientists for their contributions to the publication 

and to the spectroscopy community as a whole. 

Replicated Mirrors. 

Solutions for Instrument Designers 

Newport’s Opticon brand of replicated mirrors represents 30 years of 

manufacturing expertise in UV and FT-IR spectroscopy instrumentation providing 

replicated retroreflectors, toroidal mirrors, and off-axis parabolic mirrors. 

A great alternative to conventional optics, replicated mirror technology allows you 

to locate monolithic mirrors in otherwise inaccessible locations, enabling many 

design improvements including the ability to: 

• Improve instrument stability 

• Lower component cost 

• Reduce instrument weight and size 

• Increase ease of assembly 

We have many years of experience designing and manufacturing creative solutions 

for OEM applications, and by working with Newport’s Opticon Mirror Products 

team, you get a dedicated partner who is ready to replicate success in your design. 

To learn more, call (508) 528-4411 or visit www. newport.com/mirrors8

10 Spectroscopy 26(9) September 2011 www.spectroscopyonline.com 

News Spectrum 

Deborah Bradshaw Joins 

Spectroscopy’s Editorial Advisory Board 

Spectroscopy is pleased to announce that Deborah 

Bradshaw has joined the Editorial Advisory Board. 

Bradshaw is an analytical chemist who has been 

working the field of atomic spectroscopy for over 30 

years. She began her career working as a chemist, 

using flame atomic absorption (AA), and then migrated 

into graphite furnace in the 1980s, developing methods 

using Zeeman background-corrected techniques for 

the analysis of seawater samples. It was then a natural 

progression to migrate into the plasma techniques. For 

the past 15 years, she has been working as a consultant 

in the field of atomic spectroscopy, conducting 

training classes and giving technical support for AA 

and inductively coupled plasma coupled with optical 

emission spectroscopy and mass spectrometry (ICP- 

OES and ICP-MS). 

Bradshaw’s technical affiliations include memberships 

in the American Chemical Society and the Society for 

Applied Spectroscopy (SAS). For 14 years, Bradshaw 

was the news column editor for the Journal of Applied 

Spectroscopy, SAS’s monthly publication. She also 

has sat on several SAS committees, and from 2002 to 

2004, was the treasurer of organization. She was the 

recipient of the SAS Distinguished Service Award in 

2008, and continues to be active in that society today. 

Bradshaw has also been very involved in efforts to 

promote spectroscopy education and to provide 

support to analysts using atomic spectroscopy 

techniques. She was the Atomic Spectroscopy 

Symposia Chair for conference of the Federation of 

Analytical Chemistry and Spectroscopy Societies 

(FACSS) in 2007 and 2008, has organized technical 

symposia at both FACSS and the 

Pittsburgh Conference, has been 

a short course instructor for SAS, 

and has been a short course 

instructor at the Winter Plasma 

Conference on Spectrochemical 

Analysis since 2000. 

Deborah Bradshaw 

She continues to be a reviewer 

for publications and journals in 

her field. 

Market Profile: Handheld and Portable FT-IR 

Major technological advances have allowed the market 

for handheld and portable Fourier-transform infrared 

(FT-IR) spectroscopy to develop almost overnight. 

Demand from a variety of industries and applications 

is continuing to take shape, and many major vendors 

in the market have taken note and made sure to grab 

themselves a major stake in this fast growing area. 

Similarly to the laboratory benchtop IR 

spectroscopy market, the vast majority of portable 

and handheld IR spectrometers are based on FT-IR 

configurations. Technological 

advances over the past two 

decades in areas such as lasers, 

batteries, software, and micro 

electromechanical systems 

(MEMS) now allow for vendors 

to routinely design and build 

rugged, compact, portable 

FT-IR instruments that have 

2010 handheld and portable FT-IR demand by industry. 

the same or even better performance than benchtop 

systems of just a few years ago. 

Government applications, such as for defense, 

HazMat, and other first responders, still account for 

the largest percentage by far of industrial demand for 

portable and handheld FT-IR. However, demand from 

other sectors, including polymers and plastics, have 

become much more important. 

12% 

13% 

12% 

15% 

30% 

The competitive landscape has changed 

considerably over the past few years, with large 

diversified vendors acquiring much smaller 

companies that have largely paved the way in the 

market. In 2010, Thermo Fisher Scientific acquired 

Ahura Scientific, which was a fairly recent start-up 

that saw incredible growth and success. This year 

Agilent acquired A2 technologies, which along with 

Bruker and Smiths Detection, makes for four major 

competitors in the market. These vendors, combined 

with a few others, accounted 

18% 

Government 

Polymers & Plastics 

Paints & Coatings 

Chemicals 

Oil & Gas 

Other 

for revenues of around $65 

million for portable and 

handheld FT-IR in 2010, 

which should grow to more 

than $100 million by 2015. 

The foregoing data were 

based on SDi’s market analysis 

and perspectives report 

entitled Global Assessment Report, 11th Edition: 

The Laboratory Life Science and Analytical Instrument 

Industry, October 2010. For more information, 

contact Stuart Press, Vice President – Strategic 

Analysis, Strategic Directions International, Inc., 

6242 Westchester Parkway, Suite 100, Los Angeles, 

CA 90045, (310) 641-4982, fax: (310) 641-8851, 

www.strategic-directions.com.

TANGO. ANALYSIS TO GO. 

Instant Results with FT-NIR Spectroscopy 

Faster, simpler, more secure - with TANGO your NIR 

analysis speeds up. TANGO has exactly what users 

require of an NIR spectrometer suitable for a quality 

control lab: robustness, high precision and straightforward 

operator guidance via a touch screen user 

interface. 

The TANGO is proven FT-NIR technology by Bruker 

built into an ergonomic, design awarded body. 

Contact us for more details: www.brukeroptics.com • www.tango-nir.com 

Innovation with Integrity 

FT-NIR


Mass Spectrometry Forum 

Consequences of Finite Ion 

Lifetimes in Mass Spectrometry 

An advertising slogan suggests that “diamonds are forever,” leading to some interesting discussions 

of long-term thermodynamic stability in freshman chemistry classes. For mass spectrometry 

(MS), the finite lifetime of organic ions has practical consequences. Simply stated, we 

want ions, once formed, to survive unchanged until we either force a change in mass, charge, 

or structure (as in MS-MS analysis), or until the ions arrive at the instrument detector after 

mass analysis. Instead of millions of years for the lifetime of diamonds, our focus is shifted 

to a lifetime scale usually ranging from microseconds to milliseconds for ions derived from 

organic and biochemical compounds. As we construct more-complex instruments that process 

packets of ions in time and space, the issue of ion lifetimes grows in importance. On one end 

of the scale, groups of specialists use MS to measure the masses of very short-lived radioactive 

nuclides. On the other end of the scale, our ability to store atomic ions for very long periods in 

ion traps leads to fundamental experimental determinations in metrology. 

Kenneth L. Busch 

In teaching organic mass spectrometry (MS) with electron 

ionization, we usually invoke the Franck–Condon principle 

(1–3, for various spectroscopic applications) to describe the 

timing perspective of the ionization process and subsequent 

passage of the ions through the mass spectrometer. Classically, 

the Franck–Condon principle states that the electronic transition 

that leads to ionization of the molecule occurs much faster 

than any changes in the bonding or positions of the atoms of 

the molecule. The molecular ion thus (at least initially) retains 

the structure of the molecule from which it is formed. Ions are 

accelerated “promptly” from the source into the mass analyzer. 

If we completed the story of the timing framework, me might 

suggest that ions pass so quickly through the instrument that 

the relatively slow rate at which we scan a mass analyzer (as in a 

sector-based mass spectrometer) is of no practical consequence. 

We use the kinetic energy equation to calculate the velocity 

of ions moving through the MS system as an example of this 

framework. In any mass spectrometer, the accelerating potential 

of the source V provides the ion with a potential energy that is 

equal to the kinetic energy, defined as (1/2)mv 2 , where m is the 

mass of the ion in kilograms and v is the velocity in meters per 

second. The calculational exercise (Table I) is especially useful in 

that it links ion masses in terms of daltons (Da) to ion masses in 

kilograms and also provides a real sense of the speed of ions as 

they pass through a laboratory-scale instrument. Table I collects 

calculated results for a variety of ions, with a range of masses 

and charges, and their calculated velocities and passage through 

a 1-m linear flight path in a time-of-flight (TOF) instrument 

with 5000 V accelerating potential. The calculation easily leads 

to a discussion of where an ion spends most of its time in a mirror 

TOF system and to further consideration of the length of ion 

flight paths in other mass analyzers. 

As MS instruments for organic analyses were developed, 

scientists scanning the baseline observed reproducible signals 

of different characters than the normal stable ions in the mass 

spectrum. The signals were metastable ions (4). A metastable ion


September 2011 Spectroscopy 26(9) 13 

appears in the mass spectrum obtained 

with a magnetic-sector mass analyzer 

as a low-intensity diffuse peak (Figure 

1), contrasted with the sharp peaks for 

stable ions drawn from the source of 

the mass spectrometer and dispersed in 

normal fashion by the magnetic sector. 

A metastable signal arises due to the dissociation 

of a parent ion to a product ion, 

after acceleration from the source, and 

in a field-free region before entrance into 

the mass analyzer. This physical region 

is termed a field-free region because it is 

not subject to the acceleration potential 

that draws ions from the source and the 

ion has not yet entered the mass analyzer 

field. It is not strictly field-free, as 

focusing elements may be placed there, 

but the term persists. In a Nier-Johnson 

geometry instrument, parent ions m 1 

that 

dissociate in the first field-free region to 

a product ion m 2 

constitute a metastable 

ion m * observed in the mass spectrum at 

an apparent mass of m * = (m 2 2 /m 1 

). Furthermore, 

the kinetic energy release associated 

with the dissociation shapes the 

peak so that the observed signal is broad 

Normal “sharp” peak shape 

“Broad” peak shape for 

metastable ion transitions 

14 15 16 17 18 19 20 21 22 

m/z 

Figure 1: Different peak shapes observed for normal ions (sharp) and metastable ion transitions 

(broad) within the low-mass range on a Nier-Johnson instrument. (Created from Figure 15 in 

reference 4.)


Table I: Calculation of ion velocities and flight times through a mass spectrometer of 1-m 

flight path from source to detector, illustrated for a range of ion masses and charges 

Ion (Da) m/z Ion Velocity (m/s) Flight Time (s) 

1 + 1 9.82 × 10 5 1.02 × 10 -6 

1000 + 1000 3.11 × 10 4 3.22 × 10 -5 

100,000 + 100,000 3.11 × 10 3 3.22 × 10 -4 

100,000 10+ 10,000 9.82 × 10 3 1.02 × 10 -4 

100,000 100+ 1000 3.11 × 10 4 3.22 × 10 -5 

1,000,000 + 1,000,000 9.82 × 10 2 1.02 × 10 -3 

1,000,000 10+ 100,000 3.11 × 10 3 3.22 × 10 -4 

1,000,000 100+ 10,000 9.82 × 10 3 1.02 × 10 -4 

compared to “normal” peaks. Figure 1 

shows metastable ions observed between 

ions of m/z 14 and m/z 26 in such an 

instrument. The sharp peaks (representing 

ion beams for “normal” fragment 

ions) contrasts sharply with the diffuse 

peak shapes of the metastable ion signals. 

Metastable ions are a fingerprint of fragmentation 

reactions, just as those that 

lead to the “normal” mass spectrum. The 

insightful early works into their origins 

and use were notable. These studies led 

to determinations of the half-lives of ions 

and measurements of the few percent that 

dissociate in metastable transitions (5), 

to the inference of molecular ions when 

not otherwise observed (6), and to stereochemical 

determinations for ions (7). 

Instruments for 

Studying Metastable Ions 

Although many of these early studies 

of metastable ions derived from organic 

compounds were carried out with sectorbased 

instruments, the ions don’t “know” 

about the nature of the instrument used 

to study them. Metastable ions dissociate 

according to their structure, charge state, 

and internal energy, and our instruments 

may or may not be able to observe these 

reactions. Let’s consider metastable ions 

in a TOF instrument. In the idealized 

TOF source, all ions are formed in the 

same place at the same time and are accelerated 

through the same potential into 

the flight tube. Their race through the 

flight tube is timed, with the lighter mass 

ions arriving at the detector first (Table I). 

What happens if an ion dissociates after 

acceleration into the flight tube but before 

arrival at the detector? The fragment 

ions and neutral species continue moving 

through the flight tube at essentially the 

same velocity as the dissociating parent 

ion (8). The signal generated by the detector 

is therefore due to the coincident 

arrival of a combination of undissociated 

parent ions, fragment ions, and even fast 

neutral species. Standing discusses the 

significance of the ion-to-neutral conversion 

in his personal review of TOF-MS 

(9). Szymczak and Wittmaack discuss 

the process of ion-to-neutral conversion 

in secondary ion MS with a TOF 

instrument (10). Neutral-ion coincidence 

measurements can increase the signalto-noise 

ratios in the MS-MS spectrum 

recorded with a TOF instrument (11). 

The early study of metastable ions and 

the later redevelopment of TOF instruments 

for biomolecular analysis at higher 

masses helped to reveal the diversity of 

dissociation reactions of energized ions as 

they move through mass spectrometers 

— through a certain physical space (the 

flight path) or within a certain period 

in a constrained trap (the flight time). 

While we implicitly expect the ions to 

be stable, the ions may have other ideas. 

The advent of MS instruments other 

than sector-based instruments, and the 

almost universal use of computerized 

data acquisition, may diminish our recognition 

that metastable ion dissociations 

are inevitable. Although the footprint of 

MS instruments has been reduced, the 

total flight path and flight time for ions 

can be surprisingly long, allowing ample 

opportunity for ion dissociation. For 

example, a quadrupole mass filter may be 

approximately 25 cm in physical length, 

but ions follow an oscillating orbital path 

through the filter that is longer. Also, 

in the quadrupole mass filter, the ions 

are not accelerated to as high a velocity 

as in a sector-based instrument and are 

moving more slowly. In an ion-trap or a 

Fourier-transform (FT)-MS instrument, 

the ions orbit in the center of the trap and 

may remain there for milliseconds, or 

much longer in specialized experiments. 

In an Orbitrap instrument (Thermo 

Fisher Scientific, Waltham, Massachusetts), 

the ions are kept in the trap until 

the desired mass measurement accuracy 

is achieved, sometimes for seconds. In a 

TOF instrument with a mirror, the flight 

path is lengthened because the ions travel 

from the source to the mirror and then 

from the mirror to the detector. In any 

instrument, the velocities of the ions may 

change slightly with focusing elements, 

or much more drastically with deceleration–acceleration 

schemes. For instance, 

in a mirror TOF instrument, the ions 

spend a seemingly disproportionate time 

within the mirror; as the ion velocities are 

slowed their directional vector changes 

and the ions are then reaccelerated. 

Hybrid Instruments 

In the quest for higher performance, 

manufacturers now offer a variety of 

“hybrid” instruments for MS-MS. Hybrid 

mass spectrometers are instruments 

constructed with at least two component 

“mass” analyzers of different types, arranged 

in sequence from ion source to 

ion detector. Hybrid mass spectrometers 

can be composed of beam components 

(an ion beam moves through the component) 

or trap components (a packet 

of ions resides within the component). 

In hybrid instruments, the concepts of 

flight path and flight time become even 

more complex and the ions have ample 

opportunity to dissociate when we do not 

expect them to. Time (as in determining 

a flight time) is a malleable parameter in 

a hybrid mass spectrometer because ions 

can be transferred between hybrid instrument 

components in discrete packages 

and independent processes can occur in 

independent components. In a trap–trap 

hybrid instrument, for example, the final 

trap can be processing a population of 

product ions by mass selection or ion 

activation, or proving an accurate mass 

measurement, while the initial trap can 

be processing single-stage mass spectral 

data, or even completing lower resolution

© 2010 PerkinElmer, Inc. 400219_01. All trademarks or registered trademarks are the property of PerkinElmer, Inc. and/or its subsidiaries. 

IR READY 

TO GO 

IR spectrometry just got easier. With Spectrum Two, you 

can perform fast analyses anytime, anywhere. Bringing 

laboratory performance to non-laboratory environments, 

Spectrum Two assures the quality of your materials across multiple applications. 

Easy to use, powerful, compact and robust, it’s ideally suited to everyday 

measurements. Rely on 65 years of spectroscopy experience to help you protect 

www.perkinelmer.com/spectrumtwo

Abstract Deadline • November 1, 2011 Abstract Submission Site Opens October 1, 2011 

Co-sponsored by the Japan Society of Applied Physics* 

April 9–13 

San Francisco, CA 

ELECTRONICS AND PHOTONICS 

A 

B 

C 

D 

E 

F 

G 

H 

I 

J 

K 

L 

M 

Amorphous and Polycrystalline Thin-Film Silicon Science 

and Technology 

Heterogeneous Integration Challenges of MEMS, Sensor, 

and CMOS LSI* 

Interconnect Challenges for CMOS Technology–Materials, 

Processes, and Reliability for Downscaling, Packaging, 

and 3D Stacking 

Nanocontacts–Emerging Materials and Processing 

for Ohmicity and Rectification 

Materials and Physics of Emerging Nonvolatile Memories* 

Phase-Change Materials for Memory and Reconfigurable 

Electronics Applications 

Reliability and Materials Issues of III-V and II-VI 

Semiconductor Optical and Electron Devices and Materials II* 

Silicon Carbide–Materials, Processing, and Devices 

Recent Advances in Superconductors, Novel Compounds, 

and High-T c 

Materials* 

Organic and Hybrid-Organic Electronics 

Advanced Materials and Processes for “Systems-on-Plastic”* 

Group IV Photonics for Sensing and Imaging* 

Optical Interconnects–Materials, Performance, and Applications 

MATERIALS SCIENCE AND MATERIALS 

CHEMISTRY FOR ENERGY 

N 

O 

P 

Q 

R 

S 

T 

U 

V 

W 

Y 

Z 

One-Dimensional Nanostructured Materials 

for Energy Conversion and Storage 

Next-Generation Energy Storage Materials and Systems 

Advanced Materials and Nanoframeworks 

for Hydrogen Storage and Carbon Capture 

Titanium Dioxide Nanomaterials 

Bandgap Engineering and Interfaces of Metal Oxides for Energy 

Design of Materials for Sustainable Nuclear Energy 

Bio-inspired Materials for Energy Applications 

Materials for Catalysis in Energy 

Advanced Materials Processing for Scalable Solar-Cell 

Manufacturing II 

Nanostructured Solar Cells 

Actinides–Basic Science, Applications, and Technology 

Conjugated Organic Materials for Energy Conversion, 

Energy Storage, and Charge Transport 

NANOSTRUCTURED MATERIALS AND DEVICES 

AA 

BB 

Inorganic Nanowires and Nanotubes–Synthesis, Properties, 

and Device Applications* 

Solution Synthesis of Inorganic Films 

and Nanostructured Materials 

CC 

DD 

EE 

FF 

GG 

HH 

II 

JJ 

KK 

LL 

Hierarchically Self-assembled Materials– 

From Molecule to Nano and Beyond 

De Novo Carbon Nanomaterials 

New Functional Nanocarbon Devices* 

Nanodiamond Particles and Related Materials– 

From Basic Science to Applications 

Functional Inorganic Nanoparticle-Polymer Composites 

with Engineered Structures and Coupled Properties 

Nanocomposites, Nanostructures, and Heterostructures 

of Correlated Oxide Systems* 

Nanoscale Materials Modification by Photon, Ion, 

and Electron Beams* 

Nanoscale Thermoelectrics– 

Materials and Transport Phenomena 

Plasmonic Materials and Metamaterials 

New Trends and Developments in Nanomagnetism 

MM Topological Insulators 

BIOLOGICAL, BIOMEDICAL AND BIO-INSPIRED MATERIALS 

NN DNA Nanotechnology 

OO Structure-Function Design Strategies 

for Bio-enabled Materials Systems 

PP Manipulating Cellular Microenvironments 

QQ Mechanobiology of Cells and Materials 

RR Molecules to Materials–Multiscale Interfacial 

Phenomena in Biological and Bio-inspired Materials 

SS Structure/Property Relationships in Biological 

and Biomimetic Materials at the Micro-, Nano-, 

and Atomic-Length Scales 

TT Interfaces in Materials, Biology, and Physiology 

UU Integration of Natural and Synthetic Biomaterials 

with Organic Electronics 

VV Nanomedicine for Molecular Imaging and Therapy 

WW Plasma Processing and Diagnostics for Life Sciences* 

GENERAL MATERIALS SCIENCE 

XX 

YY 

ZZ 

Computational Materials Design in Heterogeneous Systems 

Rare-Earth-based Materials 

Transforming Education in Materials Science and Engineering 

AAA Synthesis, Fabrication, and Assembly of Functional Particles 

and Capsules 

BBB Functional Materials and Ionic Liquids 

CCC Local Probing Techniques and In-Situ Measurements 

in Materials Science 

www.mrs.org/spring2012 

2012 MRS SPRING MEETING CHAIRS 

Lara A. Estroff 

Cornell University 

lae37@cornell.edu 

Jun Liu 

Pacific Northwest National Laboratory 

jun.liu@pnl.gov 

Kornelius Nielsch 

University of Hamburg 

kornelius.nielsch@physik.uni-hamburg.de 

Kazumi Wada 

University of Tokyo 

kwada@material.t.u-tokyo.ac.jp 

DON’T MISS THESE FUTURE MRS MEETINGS! 

2012 MRS Fall Meeting & Exhibit November 26-30, 2012 

Hynes Convention Center & Sheraton Boston Hotel Boston, Massachusetts 

2013 MRS Spring Meeting & Exhibit April 1-5, 2013 

Moscone West & San Francisco Marriott Marquis San Francisco, California 

506 Keystone Drive Warrendale, PA 15086-7573 

Tel 724.779.3003 Fax 724.779.8313 

info@mrs.org www.mrs.org



MS-MS analyses in its own right. Even 

as we construct such instruments for 

discrete and separate stages of ion activation 

and analysis, a certain percentage 

of the ions will dissociate on their own 

at some point. Because the instrumental 

parameters are set to pass or preserve 

stable ions, these metastable ions are lost 

to further processing, invariably reducing 

the overall instrument sensitivity. 

Is there anything that can be done 

to reduce the metastable ion loss? As 

discussed in a previous column (12), 

pressure and vacuum are not really 

trivial. Seemingly small changes in 

pressure lead to large changes in ion 

transmission through instrument 

components simply as a result of scattering. 

Factor in processes such as 

collision-induced dissociation and 

the consequential effect grows. In a 

complex hybrid instrument, careful 

attention to the pressure profile along 

the ion flight path is crucial. Better 

pumping, leading to a lower pressure 

at crucial locations in the instrument, 

is almost always guaranteed to lead 

to better overall performance. Recent 

strategies for sampling directly at 

atmospheric pressure generate their 

own set of engineering challenges for 

the pumping system of the mass spectrometer. 

Although it may be possible 

to operate an instrument at “higher 

than optimal” pressures engendered 

by the atmospheric pressure sampling, 

its performance will invariably 

be degraded. 

In contrast to ions derived from 

organic and biological compounds, 

atomic ions have no paths to dissociation 

and more limited paths to neutralization. 

Long-lived atomic ions 

have been measured in mass spectrometers 

to determine their accurate 

masses. For example, the high-massmeasurement 

accuracy of the FT-MS 

instrument, used to great advantage 

in organic and biomolecular analysis, 

translates to atomic ion mass 

measurement as well (13). Introduction 

and maintenance of single ions 

within a Penning trap instrument, 

and mass measurements with a high 

degree of precision and accuracy, is 

a fundamental metrological experiment 

(14). Such experiments inform 

the basic foundations on which measurement 

science is based (15), but 

are unfortunately not broadly recognized 

within the community devoted 

increasingly to biomolecular analysis. 

However, the fundamental measurement 

of mass for short-lived radioactive 

nuclides depends explicitly on 

MS (16), and the exacting procedures 

developed in such work to minimize 

errors are instructive for all researchers 

in the field. 

Conclusion 

Finally, we note that trapped ions 

can be evaluated not for their mass, 

but as an optical clock (17). The mass 

of a single trapped ion is a constant, 

whether it is measured or not. An 

atomic clock has been devised based 

on optical transitions between trapped 

199 Hg + and 27 Al + ions. This highaccuracy 

clock represents a new basis 

for the measurement of time itself. 

We close this column with a quote 

(17): “The uncertainties in the atomic 

clocks reported here occur at the exciting 

intersection of relativity, geodesy, 

and quantum physics, and the total 

uncertainty of 5.2 × 10 −17 shows unprecedented 

sensitivity to gravitational 

effects and cosmological fluctuations. 

Future improvements in these atomic 

clocks will provide even more sensitive 

probes of nature.” Cosmological fluctuations? 

I always thought that instrument 

performance was somehow tied 

to phases of the moon, and I may have 

been right all along. 

References 

(1) S.E. Schwartz, J. Chem. Educ. 50, 

608–610 (1973). 

(2) R.L. Dunbrack, Jr., J. Chem. Educ. 63, 

953–955 (1986). 

(3) F. Ahmed, J. Chem. Educ. 64, 427– 

428 (1987). 

(4) R.G. Cooks, J.H. Beynon, R.M. Caprioli, 

and G.R. Lester in Metastable 

Ions (Elsevier, Amsterdam, 1973). 

(This book has been reprinted by 

the American Society for Mass 

Spectrometry.) 

(5) J.A. Hipple, Phys. Rev. 71, 594–599 

(1947). 

(6) L.A. Shadoff, Anal. Chem. 39, 1902– 

1903 (1967). 

(7) K.C. Kim and R.G. Cooks, J. Org. 

Chem. 40, 511–513 (1975). 

(8) C.R. Ponciano and E.F. da Silveira, J. 

Phys. Chem. A 106, 10139–10143 

(2002). 

(9) K.G. Standing, Int. J. Mass Spectrom. 

200, 597–610 (2000). 

(10) W. Szymczak and K. Wittmaack, Appl. 

Surf. Sci. 203–204, 170–174 (2003). 

(11) F.H. Strobel and D.H. Russell, Anal. 

Chem. 64, 2879–2881 (1992). 

(12) K.L. Busch, Spectroscopy 24(11), 

16–22, (2009). 

(13) M.V. Gorshkov, S.H. Guan, and A.G. 

Marshall, Int. J. Mass Spectrom. Ion 

Phys. 128, 47–60 (1993). 

(14) R.C. Thompson, Meas. Sci. Technol. 

1, 93–105 (1990). 

(15) F. DiFillipo, V. Natarajan, K.R. Boyce, 

and D.E. Pritchard, Phys. Rev. Letters 

73(11), 1481–1484 (1994). 

(16) http://isoltrap.web.cern.ch/ 

isoltrap/ 

(17) T. Rosenband, D.B. Hume, P.O. 

Schmidt, C.W. Chou, A. Brusch, L. 

Lorini, W.H. Oskay, R.E. Drullinger, 

T.M. Fortier, J.E. Stalnaker, S.A. 

Diddams, W.C. Swann, N.R. Newbury, 

W.M. Itano, D.J. Wineland, 

and J.C. Bergquist, Science 319, 

1808–1812 (2008). 

Kenneth L. Busch is 

amused to think that, at 

one extreme, our experiments 

define time with 

such precision and accuracy 

that we can watch for 

cosmological fluctuations. 

On another level, Samoa 

is scheduled to leap back across the International 

Dateline at the end of this year, 

losing an entire day (and a Friday at that!). 

Their last change was in 1892, apparently 

accomplished without too great an inconvenience. 

In 2011, we assume there’s 

already an ID hop app, and if there’s not, 

sooner or later (pun intended), there will 

be. This column is the sole responsibility of 

the author, who can be reached at WyvernAssoc@yahoo.com. 

For more information on 

this topic, please visit: 

www.spectroscopyonline.com/busch


The Baseline 

Maxwell’s Equations, Part III 

This is the third part of a multipart series on Maxwell’s equations of electromagnetism. 

The discussion leading up to the first equation got so long that we had to separate it into 

two parts. However, the ultimate goal of the series is a definitive explanation of these four 

equations; readers will be left to judge how definitive it is. As a reminder, figures are being 

numbered sequentially throughout this series, which is why the first figure in this column is 

Figure 16. I hope this does not cause confusion. Another note: this is going to get a bit mathematical. 

It can’t be helped: models of the physical universe, like Newton’s second law F = 

ma, are based in math. So are Maxwell’s equations. 

David W. Ball 

In the previous installment, we started introducing 

the concepts of slope and discussed how calculus 

deals with slopes of curved lines. Here, we’ll start 

with calculus again, with our ultimate goal being the 

understanding of Maxwell’s first equation. 

More Advanced Calculus 

We have already discussed the derivative, which is a 

determination of the slope of a function (straight or 

curved). The other fundamental operation in calculus is 

integration, whose representation is called an integral: 

a 

∫ f(x) dx 

[1] 

b 

where the symbol ∫ is called the integral sign and represents 

the integration operation; f(x) is called the integrand 

and is the function to be integrated; dx is the infinitesimal 

of the dimension of the function; and a and b 

are the limits between which the integral is numerically 

evaluated, if it is to be numerically evaluated. (If the integral 

sign looks like an elongated “s”, it should — Leibniz, 

one of the cofounders of calculus [with Newton], 

adopted it in 1675 to represent “sum”, since an integral 

is a limit of a sum.) A statement called the fundamental 

theorem of calculus establishes that integration and differentiation 

are the opposites of each other, a concept 

that allows us to calculate the numerical value of an integral. 

For details of the fundamental theorem of calculus, 

consult a calculus text. For our purposes, all we need 

to know is that the two are related and calculable. 

The most simple geometric representation of an integral 

is that it represents the area under the curve given 

by f(x) between the limits a and b and bound by the x 

axis. Look, for example, at Figure 16a. It is a figure of 

the line y = x or, in more general terms, f(x) = x. What is 

the area under this function but above the x axis, shaded 

gray in Figure 16a? Simple geometry indicates that the 

area is ½ units — the box defined by x = 1 and y = 1 is 1 

unit (1 × 1), and the right triangle that is shaded gray is 

one-half of that total area, or ½ unit in area. Integration 

of the function f(x) = x gives us the same answer. The 

rules of integration will not be discussed here; it is assumed 

that the reader can perform simple integration: 

1 

∫ 

1 

∫ 

1 

f(x) dx = x dx = ½ x 2 = ½ (1) 2 – ½ (0) 2 = ½ – 0 = ½ 

0 

0 

0 [2] 

It is a bit messier if the function is more complicated. 

But, as first demonstrated by Reimann in the 1850s, the 

area can be calculated geometrically for any function in 

one variable (easy to visualize, but in theory this can be

NIR, Kjeldahl, Dumas, 

Falling Number 

Sample Preparation of 

Food and Feed 

Ultra Centrifugal Mill 

ZM 200 

Knife Mill 

GRINDOMIX GM 200 

Knife Mill 


Cyclone Mill 

TWISTER

For optimum 

quality control 

Application examples TWISTER ZM 200 

Raw material 

GM 200 / 

GM 300 

Wheat + + o 

Corn o + + 

Hay/straw + + – 

Feeds 

Pig food pellets + + o 

Pet food pellets + + o 

Fish food pellets + + o 

Dry food 

Rice + + o 

Cereals + + o 

Peanuts – o + 

Almonds – o + 

Soy beans + + o 

Sun⇓ower seed o + o 

Cookies – – + 

Moist food 

Tomatoes – – + 

Cheese – – + 

Sausages – – + 

Cooked pasta – – + 

Within the RETSCH range of mills and grinders 

there is a specialist for every application. 

But what they have in common is that they 

produce a perfectly homogeneous, unaltered 

and uncontaminated sample so that the subsequent 

analysis is always trustworthy and 

meaningful. If you require professional solutions 

that combine high performance, ease 

of use, a maximum of operational safety and 

a long lifetime, then RETSCH’s equipment is 

your only choice! 

Ideal for forage, feeds and grains 

CYCLONE MILL TWISTER 

Q Rotor mill with sieve insert (1 mm or 2 mm) 

and grinding ring 

Q Sieve inserts 0.5 mm and 0.8 mm (option) 

Q 3 controlled rotor speeds 

Q Cyclone separator with 250 ml collecting bottle for quick 

extraction of sample 

Q Connection for vacuum cleaner 

Q No cross contamination thanks to easy cleaning 

Q Professional industrial design with long lifetime 

Q Convenient operating panel 

www.retsch.com/twister 

+ highly suitable 0 suitable – not suitable 

WET CHEMICAL AND ELEMENT ANALYSES 

RETSCH laboratory mills are suitable for sample preparation 

not only to NIR analysis but a variety of analytical 

methods. Achievable grind sizes of approximately 

500 microns are ideal for protein analysis according 

to Kjeldahl and Dumas. The same is true 

for the determination of falling numbers. 

The grind size is also suitable for the determination of 

fat and organic contaminants through extraction, 

resp. of inorganic contaminants through digestion. 

NEW 

Cyclone Mill 

TWISTER

SAMPLE PREPARATION TO NIR ANALYSIS 

Near Infrared Spectroscopy is 

the most important analysis 

method for the determination 

of protein content, moisture, 

fat and ash in feeds and forage. 

The advantage over classical 

methods such as Kjeldahl 

is the simultaneous determination 

of several parameters. 

Moreover, NIR spectroscopy 

is a quick method which neither 

requires consumables 

nor reagents. Therefore it is 

used whenever high sample 

throughput and great ⇓exibility 

are required. 

The identi⇒cation and quali⇒cation 

of raw materials as well 

as the quantitative analysis 

of convenience products can 

be carried out within seconds 

to guarantee highest product 

quality and safety. 

A much discussed issue related 

to NIR analysis is the 

necessity of sample preparation. 

Users often face the 

problem of having to decide 

whether sample preparation is 

required or not. 

Sample preparation to NIR 

does not require digestion or 

extraction, it is mainly about 

size reduction of the sample 

material. 

This involves two aspects: 

1. Homogenizing 

the sample 

2. Achieving the 

required grind size 

Whereas an inhomogeneous 

sample leads to systematic 

errors in the subsequent 

analysis, a sample which is too 

coarse causes statistical errors 

(see example on next page). 

MOISTURE 

FAT 

FIBERS 

Fine grinding of grains, oilseeds, corn, animal feed 

pellets, spices, dried pasta and plants, tea, cocoa and 

raw coffee 

ULTRA CENTRIFUGAL MILL ZM 200 

Q High-throughput processing of samples for NIR and ICP 

Q Large ring sieve allows for quick sample processing 

Q Option for load-controlled automatic feeder 

Q Cyclone separator for 230 ml to 4.5 l sample material. 

Optional dust extraction for optimum material discharge 

Q Heavy-duty “Powerdrive” 

Q Speed range 6,000 rpm to 18,000 rpm 

Q Wide selection of accessories 

www.retsch.com/zm200 

Ideal for samples high in water and oil content 

KNIFE MILL GRINDOMIX GM 300 

Q Homogenization of up to 4.5 liters sample material 

Q Variable speed from 500 – 4,000 rpm 

Q Autoclavable grinding tools 

Q Patented gravity lids ensure homogenization of 

the ENTIRE sample 

Q Mode for preliminary and fine grinding 

Q Sturdy industrial motor 

Q Comprehensive range of accessories 

www.retsch.com/gm300 

KNIFE MILL 


Q For up to 700 ml 

of sample material 

Q Variable speed from 2,000 

to 10,000 rpm 

www.retsch.com/gm200 

Knife Mill 

GRINDOMIX 

GM 300 

Ultra Centrifugal Mill 

ZM 200

Improved results thanks to 

correct sample preparation 

EXAMPLE: ANALYSIS OF WHEAT 

The different properties of ground and unground samples 

when analyzed with NIR are demonstrated exemplarily with 

grains of wheat. The samples were analyzed 10 times, the 

spectrometer was refilled for every measurement. The wheat 

grains were previously ground in RETSCH’s cyclone mill 

TWISTER. 

The table shows a considerable difference between ground 

and unground sample, particularly with regards to ash and 

⇒ber content. This is due to the fact that only the surface of 

the unground wheat grains is analyzed resulting in an over 

representation of the kernel shell. 

NIR spectroscopy allows to determine a series of relevant parameters 

in feeds and grains without great effort. The prevalent 

opinion is that sample preparation is not required for NIR 

analysis. However, the results presented here clearly indicate 

that it is bene⇒cial to pulverize the samples with a suitable 

laboratory mill before analyzing it, particularly if the material 

is inhomogeneous. That is the only way to guarantee 

meaningful and reliable analysis results. 

Parameter Ash Moisture 

unground wheat 

Fiber 

content 

Fat 

Protein 

average 0.10 9.80 6.90 1.38 8.46 

standard deviation 0.10 0.25 0.62 0.16 0.45 

ground wheat 

average 2.80 9.68 1.10 1.17 9.02 

standard deviation 0.03 0.09 0.05 0.03 0.07 

Fiber content 

⇒ber content 

unground wheat 

ground wheat 

sample no. 

The analysis of the unground sample clearly shows a systematic as 

well as a considerable statistic error. 

FREE TEST GRINDING 

As part of RETSCH’s professional customer support we offer our customers the individual 

advice required to find the optimum solution for their sample preparation 

task. To achieve this our application laboratories process and measure samples 

free-of-charge and provide a recommendation for the most suitable method and 

instrument. 

For more information please visit our website www.retsch.com/testgrinding 

Retsch, Inc. 

74 Walker Lane 

Newtown, PA 18940 

Toll free (866) 473-8724 

Phone (267) 757-0351 

Fax (267) 757-0358 

E-Mail info@retsch-us.com 

Subject to technical modification and errors · 99.100.1065/US-05-2011



extended to any number of dimensions) 

by using rectangles of progressively 

narrower widths, until the 

area becomes a limiting value as the 

number of rectangles goes to infinity 

and the width of each rectangle 

gets infinitely narrow — one reason 

a good calculus course begins with 

a study of infinite sums and limits! 

But I digress. For the function in 

Figure 16b, which is f(x) = x 2 , the 

area under the curve, now poorly approximated 

by the shaded triangle, is 

calculated exactly with an integral: 

1 

∫ 

0 

1 

∫ 

f(x) dx = x 2 dx = x 3 = – (0) = 

0 

1 

1 1 1 3 3 3 

[3] 

As with differentiation, integration 

can also be extended to functions 

of more than one variable. The 

issue to understand is that when 

considering functions, the space you 

need to use has one more dimension 

than variables because the function 

needs to be plotted in its own dimension. 

Thus, a plot of a one-variable 

function requires two dimensions, 

one to represent the variable 

and one to represent the value of the 

function. Figures 9 and 10 in the 

previous installment (1) are therefore 

two-dimensional plots. A twovariable 

function needs to be plotted 

or visualized in three dimensions, 

like Figures 11 or 12 in the previous 

column. Looking at the two-variable 

function in Figure 17, we see a line 

across the function’s values, with 

its projection in the (x,y) plane. The 

line on the surface is parallel to the 

y axis, so it is showing the trend of 

the function only as the variable x 

changes. If we were to integrate this 

multivariable function with respect 

only to x (in this case), we would be 

evaluating the integral only along 

this line, called a line integral. One 

interpretation of this integral would 

be that it is simply the part of the 

volume under the overall surface 

that is beneath the given line; that is, 

it is the area under the line. 

If the surface represented in 

Figure 17 represents a field (either 

scalar or vector), then the line integral 

represents the total effect of 

that field along the given line. The 

0 

formula for calculating the “total effect” 

might be unusual, but it makes 

sense if we start from the beginning. 

Consider a path whose position is 

defined by an equation P, which is 

a function of one or more variables. 

What is the distance of the path? 

One way of calculating the distance s 

is velocity v times time t, or 

s = v × t [4] 

But velocity is the derivative of position 

P with respect to time, or dP/dt. 

Let us represent this derivative as P΄. 

Our equation becomes 

s = P΄ × t [5] 

This is for finite values of distance 

and time, and for that matter, for constant 

P΄. (For example: total distance 

at 2.0 m/s for 4.0 s = 2.0 m/s × 4.0 s = 

8.0 m. In this example, P΄ is 2.0 m/s 

and t is 4.0 s.) For infinitesimal values 

of distance and time, and for a path 

whose value may be a function of the 

variable of interest (in this case, time), 

the infinitesimal form is 

ds = P΄dt [6] 

To find the total distance, we integrate 

between the limits of the initial 

position a and the final position b 

s = 

(a) 

∫ 

b 

1 

a 

P’ dt 

f(x) = x 

[7] 

(b) 

1 1 

1 

f(x) = x 2 

Figure 16: The geometric interpretation of a simple integral is the area under a function and 

bounded on the bottom by the x-axis (that is, y = 0). (a) For the function f(x) = x, the areas as 

calculated by geometry and integration are equal. (b) For the function f(x) = x 2 , the approximation 

from geometry is not a good value for the area under the function. A series of rectangles can 

be used to approximate the area under the curve, but in the limit of an infinite number of 

infinitesimally-narrow rectangles, the area is equal to the integral. 

The point is that it’s not the path P 

we need to determine the line integral 

— it’s the change in P, denoted 

as P΄. This seems counterintuitive 

at first, but hopefully the above example 

makes the point clear. It’s also 

a bit of overkill when one remembers 

that derivatives and integrals 

are opposites of each other: The 

above analysis has us determine a 

derivative and then take the integral, 

undoing our original operation, to 

get the answer. One might have just 

kept the original equation and determined 

the answer from there. We’ll 

address this issue shortly. One more 

point: It doesn’t have to be a change 

with respect to time. The derivative 

involved can be a change with 

respect to a spatial variable. This 

allows us to determine line integrals 

with respect to space as well as time. 

Suppose the function for the path 

P is a vector? For example, consider 

a circle C in the (x,y) plane having 

radius r. Its vector function is C = 

rcosθi + rsinθj + 0k (see Figure 18), 

which is a function of the variable 

θ, the angle from the positive x axis. 

What is the circumference of the circle; 

that is, what is the path length as 

θ goes from 0 to 2π, the radian measure 

of the central angle of a circle? 

According to our formulation above, 

we need to determine the derivative 

of our function. But for a vector, if 

we want the total length of the path,


Better Raman 

Solutions for PAT 

f(x,y) 

Handheld Raman for 

incoming raw material 

idenƟ⇒caƟon 

x 

y 

Figure 17: A multivariable function f(x,y) with a line paralleling the 

y axis. 

How far around? 

High sensiƟvity Raman 

for lab and on‐line 

process control 

r 

Figure 18: How far is the path around the circle? A line integral can tell 

us and it agrees with what basic geometry predicts (2πr). 

we care only about the magnitude of the vector and not 

its direction. Thus, we’ll need to derive the change in 

the magnitude of the vector. We start by defining the 

magnitude: the magnitude |m| of a three-magnitude 

(or lesser) vector is the Pythagorean combination of its 

components 

|m| = √ x 2 + y 2 + z 2 

[8] 

Enwave Optronics, Inc. 

www.enwaveopt.com 

info@enwaveopt.com 

For the derivative of the path/magnitude with respect to 

time, which is the velocity, we have 

|m’| = √ (x’) 2 + (y’) 2 + (z’) 2 

[9] 

For our circle, we have the magnitude as simply the i, 

j, and k terms of the vector. These individual terms are 

also functions of θ. We have



x 

d(r cos θ i) 

x’ = = –r sin θ i 

dθ 

d(r sin θ j) 

y’ = = –r cos θ j 

z’ = 0 

dθ 

From this we have 

[10] 

(x’) 2 = r 2 sin 2 θ i 2 

[11] 

(y’) = r 2 cos 2 θ j 2 

(and we will ignore the z part, since 

it’s just zero). For the squares of the 

unit vectors, we have i 2 = j 2 = i·i = j·j 

= 1. Thus, we have 

a 

s = P’ dt = 

b 

∫ 

2π 

∫ () 

0 

√ 

r 2 sin 2 θ + r 2 cos 2 θ dθ 

[12] 

We can factor out the r 2 term from 

each term and then out of the square 

root to get 

s = 

2π 

r 

0 

f(x,y) 

Figure 19: A surface S over which a function 

f(x,y) will be integrated. 

F 

F 

∫ √[13] 

sin 2 θ + cos 2 θ dθ 

n 

Flow 

Flow 

Figure 20: Flux is another word for amount of 

flow. (a) In a tube that is cut straight, the flux 

can be determined from simple geometry. 

(b) In a tube cut at an angle, some vector 

mathematics is needed to determine flux. 

R 

S 

y 

Because, from elementary trigonometry, 

sin 2 θ + cos 2 θ equals 1, we have 

s = (r 

2π 

2π 

∫2π 

0 

√ 

1)dθ 

∫ 

= rdθ = r . θ 

0 

0 

= r(2π – 0) = 2πr 

[14] 

This seems like an awful lot of work 

to show what we all know, that the 

circumference of a circle is 2πr. But 

hopefully it will convince you of the 

propriety of this particular mathematical 

formulation. 

Now, back to “total effect.” For 

a line integral involving a field, 

there are two expressions we need 

to consider: the definition of the 

field F[x(q),y(q),z(q)] and the definition 

of the vector path p(q), where q 

represents the coordinate along the 

path. (Note that at least initially, the 

field F is not necessarily a vector.) 

In that case, the total effect s of the 

field along the line is given by 

s = 

∫] 

F 

p [ 

x(q), y(q), z(q) . p’(q) dq 

[15] 

The integration is over the path p, 

which needs to be determined by 

the physical nature of the system of 

interest. Note that in the integrand, 

the two functions F and |p΄| are multiplying 

together. 

If F is a vector field over the vector 

path p(q), denoted F[p(q)], then the 

line integral is defined similarly 

s = 

F 

p 

p(q) . 

[ p’(q) dq 

[16] 

∫ ] 

Here, we need to take the dot product 

of the F and p΄ vectors. 

A line integral is an integral over 

one dimension that gives, effectively, 

the area under the function. We can 

perform a two-dimensional integral 

over the surface of a multidimensional 

function, as pictured in Figure 

19. That is, we want to evaluate 

the integral 

∫ s 

g(x,y,z) dS 

[17] 

where g(x,y,z) is some scalar function 

on a surface S. Technically, 

this expression is a double integral 

BALL MILLS 

Planetary Ball Mill 

PM 100 

RETSCH's ball mills are 

powerhouses with ultimate 

grinding efficiency and 

unparalleled versatility 

■ 4 different planetary ball mills for 

ultra-fine grinding to sub-micron 

sizes 

■ 2 models of high-impact mixer mills 

for dry, wet, cryogenic grinding and 

cell disruption 

■ CryoMill for automatic cryogenic 

grinding at -196 °C 

■ great variety of grinding containers, 

in sizes from 1.5 ml to 500 ml, 

in 7 different materials 

■ all-digital controls & memory for 

perfect reproducibility of results 

■ ease of use and outstanding safety 

features 

www.retsch.com/milling 

CryoMill 

Planetary Ball Mill 

PM 400 

Mixer Mill 

MM 400 

1-866-4-RETSCH


y 

z 

x 

F = xi + yj 

F = 2 

n k 

(x,y,z) 

z 

Figure 22: The divergence of the vector field F 

= xi + yj is 2, indicating a constant divergence, 

a constant spreading out, of the field at any 

point in the (x,y) plane. 

x 

y 

x 

Figure 21: What is the surface integral of a cube as the cube gets infinitely small? 

y 

over two variables. This is generally 

called a surface integral. 

The mathematical tactic for 

evaluating the surface integral is 

to project the functional value into 

the perpendicular plane, accounting 

for the variation of the function’s 

angle with respect to the projected 

plane. The proper variation 

is the cosine function, which gives 

you a relative contribution of 1 if 

the function and the plane are parallel 

(for example, cos 0° = 1) and 

a relative contribution of 0 if the 

function and the plane are perpendicular 

(for example, cos 90° = 0). 

This automatically makes us think 

of a dot product. If the space S is 

being projected into the (x,y) plane, 

then the dot product will involve 

the unit vector in the z direction, 

or k. (If the space is projected into 

other planes, other unit vectors 

are involved, but the concept is the 

same.) If n(x,y,z) is the unit vector 

that defines the line perpendicular 

to the plane marked out by g(x,y,z) 

(called the normal vector), then 

the value of the surface integral is 

given by 

∫ R 

g(x,y,z) 

∫dx 

n(x,y,z) . 

dy 

k 

[18] 

where the denominator contains a 

dot product and the integration is 

over the x and y limits of the



x 

Force from other 

particle 

+ - 

Force from other 

particle 

Figure 24: It is an experimental fact that charges exert forces on each 

other. That fact is modeled by Coulomb’s law. 

Figure 23: A nonconstant divergence is illustrated by this onedimensional 

field F = x 2 i whose divergence is equal to 2x. The 

arrowheads represent length of the vector field at values of x = 1, 2, 3, 

4, and so forth. The greater the value of x, the farther apart the vectors 

get — that is, the greater the divergence. 

region R in the (x,y) plane of Figure 19. The dot 

product in the denominator is actually fairly easy 

to generalize. When that happens, the surface 

integral becomes 

g(x,y,z) 

1 

f 

x 

2 2 

f 

y 

dx dy 

[19] 

where f represents the function of the surface and g represents 

the function you are integrating over. Typically, 

to make g a function of only two variables, you let z = 

f(x,y) and substitute the expression for z into the function 

g, if z appears in the function g. 

If, instead of a scalar function g we had a vector function 

F, the above equation gets a bit more complicated. 

In particular, we are interested in the effect that is normal 

to the surface of the vector function. Because we 

previously defined n as the vector normal to the surface, 

Phone 801.225.0930 

www.moxtek.com 

See the light 

Inorganic Absorptive Polarizers are 

extremely useful in optical systems where 

stray light is a key concern. Designed 

specifically for the blue, green, and red 

channels, these polarizer’s help fine-tune 

your system to reduce the amount of 

reflected light. 

Moxtek Inorganic Absorptive Polarizers: 

› Maximize the power of projected light 

› Operates in harsh environment 

› No degradation over the life of the system


F ndS 

s 

[20] 

r 

q 1 

For a vector function F = F x 

i + F y 

j + F z 

k and a surface 

given by the expression f(x,y) = z, this surface integral is 

F ndS 

s 

R 

f f 

F x 

F y 

F z 

x y 

dx dy 

[21] 

This is a bit of a mess! Is there a better, easier, more concise 

way of representing this? 

A Better Way 

There is a better way to represent this last integral, but 

we need to back up a bit: What exactly is F∙n? Actually, 

it’s just a dot product, but the integral 

r 

F ndS 

s 

[22] 

Figure 25: A charge in the center of a spherical shell with radius r has a 

normal unit vector equal to r, in the radial direction and with unit length, 

at any point on the surface of the sphere. 

we’ll use it again: We want the surface integral involving 

F∙n, or 

5o th Anniversary 

Celebrating 

Innovation 

in Analysis 

is called the flux of F. The word flux comes from the 

Latin word fluxus, meaning flow. For example, suppose 

you have some water flowing through the end of 

a tube, as represented in Figure 20a. If the tube is cut 

straight, the flow is easy to calculate from the velocity 

of the water (given by F) and the geometry of the tube. 

If you want to express the flow in terms of the mass of 

water flowing, you can use the density of the water as 

a conversion. But what if the tube isn’t cut straight, as 

shown in Figure 20b? In this case, we need to use some 

more complicated geometry — vector geometry — to 

determine the flux. In fact, the flux is calculated using 

the last integral in the previous section. Therefore, flux 

is calculable. 

Consider an ideal cubic surface with the sides parallel 

to the axes, as shown in Figure 21, that surrounds the 

point (x,y,z). This cube represents our function F and we 

want to determine the flux of F. Ideally, the flux at any 

point can be determined by shrinking the cube until it 

gets to a single point. We will start by determining the 

flux for a finite-sized side, then take the limit of the flux 

as the size of the side goes to zero. If we look at the top 

surface, which is parallel to the (x,y) plane, it should be 

obvious that the normal vector is the same as the k vector. 

For this surface by itself, the flux is then 

F kdS 

s 

[23] 

If F is a vector function, its dot product with k eliminates 

the i and j parts (since i∙k = j∙k = 0) and only the z- 

component of F remains. Thus, the integral above is just 

Join the celebration! For 50 years, scientists and researchers have 

enhanced their professional development by attending the East Coast’s largest 

analytical event. And this year’s golden anniversary symposium will be bigger 

and better than ever. Enjoy our daily anniversary festivities while experiencing 

the latest innovations in analysis at our courses, presentations, and exposition. 

For the full agenda, visit www.eas.org or call (732) 449-2280. 

www.eas.org 

s F dS z 

[24] 

If we assume that the function F z 

has some average 

value on that top surface, then the flux is simply that 

average value times the area of the surface, which we 

will propose is equal to Δx∙Δy. We need to note, though, 

that the top surface isn’t located at z (the center of the



cube), but at z + Δz/2. Therefore, we 

have for the flux at the top surface 

z 

top flux F z x,y,z x y 

2 

[25] 

where the symbol ≈ means “approximately 

equal to.” It will become 

“equal to” when the surface area 

shrinks to zero. 

The flux of F on the bottom side 

is exactly the same except for two 

small changes. First, the normal 

vector is now –k, so there is a negative 

sign on the expression. Second, 

the bottom surface is lower than the 

center point, so the function is evaluated 

at z – Δz/2. Thus, we have 

z 

bottom flux F z 

x,y,z x y 

2 

[26] 

The total flux through these two 

parallel planes is the sum of the two 

expressions 

change in z, the first term in the product 

above is simply the definition of the 

derivative of F z 

with respect to z! Of 

course, it’s a partial derivative, because 

F depends on all three variables, but we 

can write the flux more simply as 

flux 

F z 

z 

V 

[31] 

A similar analysis can be performed 

for the two sets of parallel planes; 

only the dimension labels will 

change. We ultimately get 

total flux 

F x 

x 

F y 

F 

V V V x F y 

V 

y z x y z 

F z F z 

[32] 

(Of course, as Δx, Δy, and Δz go to 

zero, so does ΔV, but this doesn’t affect 

our end result.) The expression 

in the parentheses above is so useful 

that it is defined as the divergence of 

the vector function F: 

FDM Raman Minerals 

z 

flux F z x,y,z x y F z 

2 

x,y,z 

z 

2 

x y 

[27] 

We can factor the ΔxΔy out of both 

expressions. Now, if we multiply this 

expression by Δz/Δz (which equals 

1), we have 

flux 

z 

F z x,y,z F 

2 z 

x,y,z 

z 

2 

We rearrange: 

flux 

x y 

z 

z 

[28] 

Standard Range 

•FDMRamanMineralsBundleSR,4209spectra 

•FDMRamanMinerals514SR,471spectra 



Over 6000 spectra 

Unmatched Quality 

Samples validated with Raman, FTIR, XRD and Electron Microprobe. 

Sample curation and data collection at the Univ. of Arizona. 

Over 2000 mineral species. 

Extended Range 

•FDMRamanMineralsBundleER,1842spectra 

•FDMRamanMinerals532ER,826spectra 



z 

z 

F z x,y,z F 

2 z x,y,z 

2 

x y z 

z 

[29] 

and recognize that ΔxΔyΔz is the 

change in volume of the cube, ΔV: 

flux 

F z x,y,z 

z 

z 

F x,y,z 

2 z 

2 

z 

V 

[30] 

As the cube shrinks, Δz approaches 

zero. In the limit of infinitesimal 

sales@fdmspectra.com 

608-236-9145 Fax: 608-236-9170 

www.fdmspectra.com


divergence of F 

F x 

F y F z 

x y z 

where F F x i F y j F z k 

[33] 

Because divergence of a function is 

defined at a point and the flux (two 

equations above) is defined in terms 

of a finite volume, we can also define 

the divergence as the limit as volume 

goes to zero of the flux density (defined 

as flux divided by volume): 

divergence of F 

(total flux) 

lim 

V 0 

F x 

F y F z 

x y z 

1 

V s 

F ndS 

lim 

1 

( 

V 0 

V 

There are two abbreviations to 

indicate the divergence of a vector 

function. One is to simply use the 

abbreviation “div” to represent divergence: 

div F 

[34] 

x y z 

[35] 

F x 

F y F z 

The other way to represent the divergence 

is with a special function. 

The function ∇ (called “del”) is defined 

as 

i j k 

x y z 

If one were to take the dot product 

between ∇ and F, we would get the 

following result: 

F i j k 

x y z 

F x 

F y F z 

x y z 

[36] 

F x i F y j F z k 

[37] 

which is the divergence! Note that, 

although we expect to get nine terms 

in the dot product above, cross terms 

between the unit vectors (like i∙k or 

k∙j) all equal zero and cancel out, while 

like terms (that is, j∙j) all equal 1 because 

the angle between a vector and 

itself is zero and cos 0 = 1. As such, our 

nine-term expansion collapses to only 

three nonzero terms. Alternately, one 

can think of the dot product in terms 

of its other definition: 

a∙b = Σa i 

b i 

= a 1 

b 1 

+ a 2 

b 2 

+ a 3 

b 3 

[38] 

where a 1 

, a 2 

, and so forth are the 

scalar magnitudes in the x, y, etc., 

directions. So, the divergence of a 

vector function F is indicated by 

divergence of F = ∇∙F 

[39] 

What does the divergence of a 

function mean? First, note that the 

divergence is a scalar, not a vector, 

field. No unit vectors remain in the 

expression for the divergence. This 

is not to imply that the divergence 

is a constant — it may in fact be 

a mathematical expression whose 

value varies in space. For example, 

for the field 

F = x 3 i [40] 

the divergence is 

∇∙F = 3x 2 [41] 

which is a scalar function. Thus, the 

divergence changes with position. 

Divergence is an indication of how 

quickly a vector field spreads out at 

any given point; that is, how fast it 

diverges. Consider the vector field 

F = xi + yj 

[42] 

which we originally showed in Figure 

13 of the last column and are 

reshowing in Figure 22. It has a 

constant divergence of 2 (easily verified), 

indicating a constant “spreading 

out” over the plane. However, for 

the field 

F = x 2 i [43] 

whose divergence is 2x, the vectors 

get farther and farther apart as x increases 

(see Figure 23). 

Maxwell’s First Equation 

If two electric charges were placed in 

space near each other, as is shown in 

Figure 24, there would be a force of 

attraction between the two charges. 

The charge on the left would exert a 

force on the charge on the right, and 

vice versa. That experimental fact 

is modeled mathematically by Coulomb’s 

law, in which a vector form is 

F 

q 1 

q 2 

r 

r 2 

[44] 

where q 1 

and q 2 

are the magnitudes 

of the charges (in elementary units, 

where the elementary unit is equal to 

the charge on the electron) and r is 

the scalar distance between the two 

charges. The unit vector r represents 

the line between the two charges q 1 

and q 2 

. The modern version of Coulomb’s 

law includes a conversion factor 

between charge units (coulombs, 

C) and force units (newtons, N), and 

is written as 

F 

q 1 

q 2 r 

4 0r 2 

[45] 

where ε 0 

is called the permittivity of 

free space and has an approximate 

value of 8.854… × 10 -12 C 2 /Nm 2 . 

How does a charge cause a force 

to be felt by another charge? Michael 

Faraday suggested that a charge had 

an effect in the surrounding space 

called an electric field, a vector field, 

labeled E. The electric field is defined 

as the Coulombic force felt by 

another charge divided by the magnitude 

of the original charge, which 

we will choose to be q 2 

: 

E 

F 

q 2 

4 

q 1 

r 

0r 2 

[46] 

where in the second expression we 

have substituted the expression for F. 

Note that E is a vector field (as indicated 

by the bold-faced letter) and is 

dependent on the distance from the 

original charge. E also has a unit vector 

that is defined as the line between 

the two charges involved, but in this 

case the second charge has yet to be 

positioned, so in general E can be 

thought of as a spherical field about 

the charge q 1 

. The unit for an electric 

field is newton per coulomb, or N/C. 

Because E is a field, we can pretend 

it has flux — that is, something is 

“flowing” through any surface that 

encloses the original charge. What is



flowing? It doesn’t matter; all that matters is that we can define 

the flux mathematically. In fact, we can use the definition 

of flux given earlier. The electric flux Φ is given by 

E ndS [47] 

s 

which is perfectly analogous to our previous definition 

of flux. 

Let us consider a spherical surface around our original 

charge that has some constant radius r. The normal 

unit vector n is simply r, the radius unit vector, since the 

radius unit vector is perpendicular to the spherical surface 

at any of its points (Figure 25). Because we know the 

definition of E from Coulomb’s law, we can substitute 

into the expression for electric flux 

q 1 r r dS 

s 4 [48] 

0r 2 

The dot product r∙r is simply 1, so this becomes 

q 1 dS [49] 

s 4 0r 2 

If the charge q 1 

is constant, 4 is constant, π is constant, 

the radius r is constant, and the permittivity of free 

space is constant, these can all be removed from the integral 

to get 

q 1 dS [50] 

4 0r 2 s 

What is this integral? Well, we defined our system as a 

sphere, so the surface integral above is the surface area 

of a sphere. The surface area of a sphere is known: 4πr 2 . 

Thus, we have 

q 1 

4 r 

4 0r 2 

[51] 

2 

The 4, the π, and the r 2 terms cancel. We are left with 

q 1 

0 

Recall, however, that we previously defined the divergence 

of a vector function as 

div F 

F x 

F y F z 

x y z 

lim 

V 0 

[52] 

1 1 

(total flux) lim F ndS 

V 

V 0 

V s 

[53] 

Note that the integral in the definition has exactly the 

same form as the electric field flux Φ. Therefore, in 

terms of the divergence, we have for E 

div E 

lim 

V 0 

1 

lim 

1 

1 

E ndS lim 

V 

V 0 

s 

V V 0 V [54] 

where we have made the appropriate substitutions to get the 

final expression. We will rewrite this last expression as 

div E 

lim 

V 0 

V 

q 1 

0 

[55] 

The expression q 1 

/ΔV is simply the charge density at a 

point, which we will define as ρ. This last expression 

simply becomes 

div E [56] 

This equation is Maxwell’s first equation of electromagnetism. 

It is also written as 

E [57] 

Maxwell’s first equation is also called Gauss’ law, after 

Carl Friedrich Gauss, the German polymath who first 

determined it but did not publish it. (It was finally published 

in 1867 after his death by his colleague William 

Weber; Gauss had a habit of not publishing much of his 

work, and his many contributions to science and mathematics 

were only realized posthumously.) 

In the next installment, we will expand on our discussion 

by looking at Maxwell’s second equation. In that case, 

we will be concerned with our old friend magnetism. 

References 

(1) D.W. Ball, Spectroscopy 26(6), 14–21 (2011). 

(2) B. Baigrie, Electricity and Magnetism (Greenwood Press, 

Westport, Connecticut, 2007). 

(3) D. Halliday, R. Resnick, and J. Walker, Fundamentals of 

Physics 6th Ed. (John Wiley and Sons, New York, New 

York, 2001). 

(4) J.E. Marsden and A.J. Tromba, Vector Calculus 2nd Ed. (W. 

H. Freeman and Company, 1981). 

(5) H.M. Schey, Div, Grad, Curl, and All That: An Informal Text 

on Vector Calculus 4th Ed. (W. W. Norton and Company, 

New York, New York, 2005). 

David W. Ball is normally a professor of 

chemistry at Cleveland State University in Ohio. 

For a while, though, things will not be normal: 

starting in July 2011 and for the commencing 

academic year, David will be serving as 

Distinguished Visiting Professor at the United 

States Air Force Academy in Colorado Springs, 

Colorado, where he will be teaching chemistry 

to Air Force cadets. He still, however, has two books on spectroscopy 

available through SPIE Press, and just recently published two new 

textbooks with Flat World Knowledge. Despite his relocation, he still 

can be contacted at d.ball@csuohio.edu. And finally, while at USAFA 

he will still be working on this series, destined to become another 

book at an SPIE Press web page near you. 

For more information on this topic, please visit: 

www.spectroscopyonline.com/ball


Focus on Quality 

Periodic Reviews of 

Computerized Systems, Part I 

In the first of a two part series, this month’s column looks at interpreting the Annex 11 regulations 

and understanding the principles of a periodic review. The second part will discuss how to carry out 

the review and report it. 

R.D. McDowall 

In my last Focus on Quality column we looked at the 

new European Union Good Manufacturing Practice 

(EU GMP) regulations, fousing on Annex 11 (computerized 

systems) and Chapter 4 (documentation) (1) that 

became effective on June 30 of this year. A new requirement 

in Annex 11 (2) is for periodic evaluation or periodic 

review. The regulation states in clause 11, “Computerized 

systems should be periodically evaluated to confirm that 

they remain in a valid state and are compliant with GMP. 

Such evaluations should include, where appropriate, the 

current range of functionality, deviation records, incidents, 

problems, upgrade history, performance, reliability, security, 

and validation status reports.” 

Some of the interpretations of this clause are 

• You have to conduct periodic reviews of computerized 

systems. 

• There are no exceptions to this regulation (for example, 

only critical systems need to be evaluated); all systems 

must be reviewed. 

• The frequency of the review is determined by the company’s 

quality assurance or laboratory management and justified 

where necessary to an inspector. Implicit in this statement 

is that you should apply a risk assessment to determine the 

frequency. Also, it is explicitly stated in clause 1 of Annex 11 

that risk assessment is conducted throughout the life cycle 

of a computerized system. 

• The aim of any review is to ensure that the system is compliant 

with the applicable regulations and that it remains in a 

validated state over the time period since the last review. 

• The scope of the periodic review can cover the last full 

validation, change control records since the last validation, 

problems and their resolution, user account management, 

user training, and IT support such as data backup. 

What is not stated in the regulation however, is the formality 

of the process. So how can we demonstrate to an inspector 

that periodic reviews have been carried out? Unless the reviews 

are formally documented, then you can’t; it’s as simple as that. 

So we will look at the overall process of a periodic review in 

this column and then in the next installment we will examine 

the practicalities of performing and reporting such a review. 

A Small Regulatory Problem 

Why perform a periodic review? This is probably one question 

that you may ask when reading the section above. In 

life, it is always better to use real examples to illustrate points 

you are trying to make because it demonstrates that other 

organizations can sometimes make bigger mistakes than you 

do. Take, for example, the following citation from a Food and 

Drug Administration (FDA) warning letter (3): 

6. Your firm failed to check the accuracy of the input to and output 

from the computer or related systems of formulas or other records or 

data and establish the degree and frequency of input/output verifications 

[21 CFR § 211.68(b)]. 

For example, the performance qualification of your 

system software failed to include verification of the expiration 

date calculations in the system. In addition, there is no 

established degree and frequency of performing the verification. 

Discrepancy reports have documented that product labeling with 

incorrect expiration dates have been created and issued for use.



Your response states that you opened 

Investigation T-139 and you provide a 

January 29, 2010 through February 26, 

2010 completion timeline. You have not 

provided a response to correct this violation 

and establish a corrective action 

plan to assure that computer systems are 

properly qualified. 

Planning 

phase 

(all systems) 

Periodic review/ 

audit SOP 

Computerized 

system inventory 

Periodic review 

schedule for 

year 

Systems classfied 

as critical 

major or minor 

The point is that the initial validation 

failed to check calculations in a 

computer system resulting in drug 

labels that were printed with incorrect 

expiry dates on them. Who picked up 

on the problem? The inspector! If the 

company had conducted a periodic 

review, this problem should have been 

identified by the reviewer, since it is an 

explicit requirement of the US GMP 

regulations, as noted in the warning 

letter. It is an obvious point for potential 

problems with any computerized 

system and the issue should have been 

identified and resolved long before the 

inspector strolled through the door for 

tea and cookies. 

What’s in a Name? 

Although the Annex 11 regulation 

talks about a periodic evaluation (I 

have called it a periodic review), there 

are also laboratory audits carried 

out by the quality assurance departments. 

So are periodic evaluations, 

periodic reviews, or audits the same, 

or are they different? In my opinion, 

periodic reviews or periodic evaluations 

are one and the same, and are 

focussed on a computerized system, 

the process it automates, and the 

support processes for it. In contrast, 

an audit can cover a computerized 

system, a laboratory process, quality 

system, or a subset of any portion of 

the laboratory. Therefore, an audit 

can be the same as a periodic review 

or evaluation, but can also be a wider 

check of laboratory operations to 

ensure compliance with regulations 

and internal procedures. An audit 

also can cover computerized systems 

that are part of the process, but generally 

the scope of an audit is wider 

than a periodic review. Therefore, 

looked at from another perspective, 

periodic reviews are a subset of laboratory 

audits. Thus, in this column I 

will refer only to periodic reviews but 

this will include periodic evaluation 

Execution 

phase 

(per system) 

Plan periodic 

review & 

read key 

documents 

Opening meeting 

introductions 

and objectives 

Conduct review 

and check past 

corrective 

actions 

and general audits that include computerized 

systems. 

Overview of a Periodic Review 

The topic of a periodic review that 

we will discuss is shown in Figure 

1 and consists of two phases: planning 

and execution. 

So we have established that the periodic 

review is an independent audit of 

a computerized system to determine if 

the system has maintained its validation 

status and, as said before, it is also 

a planned and formal activity. The 

first requirement for conducting a review 

is a standard operating procedure 

(SOP) covering the whole process. As a 

periodic review is a subset of an audit, 

the audit SOP should be relatively simple 

to adopt for a computerized system 

or you can use an existing audit SOP 

with a subsection for periodic reviews. 

The whole process should be described 

in the audit/review SOP and is shown 

in Figure 1. 

I have depicted the process as two parts: 

• The planning phase (covering all systems). 

This links the inventory of computerized 

systems for the laboratory 

with a risk classification of each system 

(the figure suggests critical, major, or 

Select system 

for review 

Conducted under the periodic 

review/audit SOP 

Reviewer’s 

closed meeting 

Closing meeting 

Figure 1: Flow chart for a periodic review or audit of a computerized system. 

Audit report 

and 

action plan 

minor, but this is only a suggestion) 

to the SOP for periodic reviews and 

audits and the annual self-inspection 

schedule. The principle is that the 

critical systems are reviewed more frequently 

than major or minor systems, 

and major systems are reviewed more 

frequently than minor ones. The periodicity 

of review for each type of system 

is determined by your company. 

• The execution phase (for each system 

reviewed). For each system selected for 

review there is a common process that 

consists of planning and preparation 

for the review, the opening meeting, 

performing the audit, including a check 

on the effectiveness of corrective actions 

from a previous review, the reviewer’s 

closed meeting where the observations 

are examined to determine if there are 

any findings or noncompliances, the 

closing meeting where findings and 

observations are discussed, and finally 

the writing of the review report and an 

action plan for any corrective actions or 

preventative actions. 

In this installment, we will focus 

mostly on the planning phase and will 

present the execution phase in an overview. 

The next installment will cover 

the execution phase in more detail.


Simplify 

the Difficult... 

Characterize pigments and dyes in 

precious works of art 

Select conservation materials 

matching those of the original paint 

Identify, verify, and authenticate 

Analyze art and other challenging 

samples with precision and confidence 

...with PIKE FlexIR in 

your FTIR Spectrometer 

www.piketech.com 

tel: 608-274-2721 

Objectives of a Periodic Review 

There should be two main goals for a periodic review of a 

computerized system: 

• To provide independent assurance to the process owner 

and senior management that controls are in place around 

the system being reviewed and are functioning correctly. 

The system is validated and controls are working adequately 

to maintain the validation status. 

• To identify those controls that are not working and to help 

the process owner and senior management improve them 

and thus eliminate the identified weaknesses. The impact of 

a finding may be applicable to a single computerized laboratory 

system or all systems in a laboratory. 

It is the second objective that is the most important, in my 

view. Moreover, it is an important outcome from any periodic 

review for senior management to realize that some controls 

may require systematic resolution. If a problem is found in a 

procedure that is used for all systems, the resolution of this 

may affect all computerized systems used in the laboratory 

rather than just the one being reviewed. 

Who Performs a Periodic Review? 

Annex 11 does not say who should carry out the periodic review. 

So let’s consider the possibilities: 

• The process owner (the laboratory person who is responsible 

for the system) 

• The system owner (the person responsible for the availability 

and support of the system) 

• Quality assurance (QA) 

Hmmm, I can guess some of your answers. The point I 

want to make is that people directly involved with a computerized 

system have a vested interest in their system and 

cannot make an objective decision if an activity is under 

control and in compliance or not. QA may be appropriate 

to conduct a periodic review, but the individuals have to 

know about computerized system validation and understand 

the regulations and company procedures in relation 

to computerized systems; not many in QA fit these criteria. 

So to help us answer the question, what do the regulations 

say about this? European Union GMP chapter 9 (4) 

discusses self inspections (for example, audits and periodic 

reviews) in about two-thirds of a page, and the key elements 

of these regulations can be summarized as follows: 

• Regulated activities should be examined at intervals to ensure 

conformance with regulations. 

• Self inspections must be preplanned. 

• Self inspections should be conducted by independent 

and competent persons. 

• Self inspections should be recorded and contain all the observations 

made during the inspections. 

• Where applicable, corrective actions should be proposed. 

• Completion of the corrective actions should also be recorded. 

So, from the perspective of the European regulations, 

we need a periodic review to be independent to ensure an 

objective and not subjective approach to evaluating your 

computerized spectrometer system. Indeed, the definition



Review depth 

instrument 

scope 

HPLC MS-MS detector 

System 01 

MS software 

HPLC 

MS-MS detector MS software 

PIKE FlexIR 

System 02 

Central 

network 

storage 

HPLC 

MS-MS detector 

MS software 

System 03 

Data processing 

workstation 

MS software 

Laboratory 

scope 

IT dept 

scope 

Review breadth 

system scope 

Figure 2: Scoping the periodic review of a computerized system. 

of independent is “not influenced or controlled by others; 

thinking or acting for oneself” (5). If a person who knew 

the system well were to perform a periodic review there is 

the possibility that he or she could miss something because 

it was familiar, that an independent reviewer could find. 

There is also the human tendency of a person involved in 

a system to focus on what they were doing well rather than 

the independent person who would be focusing on finding 

activities that were not compliant or could be done in a 

more efficient way. Therefore, independence of the person 

conducting a periodic review is of prime importance. 

Skills and Training of the Reviewer 

There are a number of requirements necessary for a person to 

effectively conduct a periodic review. These are 

• Knowledge of the current good laboratory practice 

(GLP) or good manufacturing practice (GMP) regulations 

and the associated guidance documents issued by 

regulatory agencies or industry bodies. At a minimum, 

this knowledge needs to be in the same good practice 

discipline that the laboratory works to, but knowledge 

of the other requirements of good practice disciplines 

is an advantage because one discipline can be vague 

on a specific point that another might have more detail 

on. For example, in GMP there are no regulatory 

agency guidelines for the SOPs required for a computerized 

system, but the FDA has issued one for clinical 

investigations (6), where a minimum list of procedures 

can be found in Appendix A. 

• Note that the knowledge of regulations above said “current.” 

This criterion is included because the regulations 

and guidelines are changing at an increasing rate, especially 

in the European Union, where it is easier and 

quicker to change the regulations, as we have seen with 

Annex 11 itself (1). 

• Experience working with computerized systems and 

knowing where (noncompliance) “bodies” can be buried 

and where bad practices can occur. 

This unique accessory brings IR light 

directly to the object through highly efficient 

and durable hollow waveguides. ATR (including 

diamond), diffuse reflectance and specular 

reflectance probes offer a wide range of sampling 

modes and penetration depths. The probes are 

small and easy to handle allowing analysis of 

small spots with reliability and confidence. Hook 

up the FlexIR to your spectrometer and instantly 

gain high sensitivity and sampling flexibility – not 

only for analysis of art but many other applications. 

FTIR sampling made easier 

PIKE Technologies 


tel: 608-274-2721


Vertical 

review/ 

audit 

Figure 3: Types of audit or periodic review. 

• An understanding of the current 

procedures used by the company, 

division, or laboratory for implementing 

and operating validated 

computerized systems. This is the 

interpretation of the regulations and 

guidance for the laboratory staff to 

work with that need to be both current 

and flexible. 

• An open and flexible approach, 

coupled with the understanding that 

there are many ways of being in control. 

Therefore, the reviewer’s ways 

of validating a computerized system 

and maintaining its validated 

state, or indeed those in the good 

automated manufacturing practice 

(GAMP) guide (7) and GAMP Good 

Practice Guide, Risk Based Approach 

to the Operation of GXP Computerized 

Systems (8) are not the only 

way of working. As Judge Jenkins 

stated in the case of the FDA versus 

Utah Medical, “Many roads lead to 

Rome”; the fact that a laboratory 

does something different to what 

you think it should do should not 

preclude it from being compliant (9). 

We will return to this point again 

when we discuss planning the audit. 

• Finally, good interpersonal skills 

coupled with a hide as thick as an 

elephant’s. The reviewer needs to ask 

open questions to understand what 

process is being carried out and investigate 

with pertinent questions to 

Horizontal review/audit 

Diagonal 

review/audit 

indentify if the work is adequate or 

if there are noncompliances. Persuasion 

may be required to change ways 

of working and a hide as thick as an 

elephant’s may be needed to ignore 

any personal remarks or insults that 

may come your way. 

So that outlines a periodic reviewer’s 

skill set. Now the reviewers have 

to perform the review, which we will 

discuss in part II of this series. 

How Critical Is Your System? 

Putting the heading in a different way: 

Do we need to do a periodic review 

for all computerized systems? Well, 

the simplest answer to that question 

is to go back to clause 11 of Annex 

11, quoted at the start of this column. 

It says “computerized systems,” not 

critical ones or selected ones but all 

computerized systems. Therefore, this 

implies the need for categorization of 

computerized systems according to 

risk. Figure 1 shows the planning process, 

from the inventory to the annual 

schedule of periodic reviews to be conducted 

within an organization. 

The starting point is the inventory 

of computerized systems contained in 

the laboratory validation master plan 

(10) that should be categorized according 

to risk. Some of the risk categories 

include critical, major, minor, no impact 

on good x practice (GxP), or high, 

medium, and low. You will want the 

most critical systems to be reviewed 

most often, as they pose the highest 

risk, and the lowest priority systems 

will be reviewed less frequently, as they 

pose the lowest risk. Most of the laboratory 

computerized systems featured 

in FDA warning letters are networked 

systems with multiple users, because 

they have the greatest impact. 

From the inventory there will be 

developed a listing of the most critical 

systems: These will have the most frequent 

reviews to ensure that they are 

in control, with decreasing frequency 

for the major and minor systems. A 

review schedule for all computerized 

systems in the laboratory would be 

drawn up for the coming year. Typically, 

the schedule for the year will 

be written by the person responsible 

in QA the previous year and will list 

all systems to be reviewed and the 

months in which this will happen. 

When to Perform a Review? 

In my opinion, there are three or four 

possible times to review a computerized 

system: 

• Before operational release of a system. 

This is to ensure that system 

development has been undertaken 

according to corporate standards 

and the validation plan. You may 

think that with all the planning 

and documentation produced in a 

validation, this is the last time to 

perform a review. However, I believe 

that this is the right time, for the 

simple reason that if something has 

been missed from the validation of 

a critical system, such as checking 

that a calculation works correctly, 

do you really want to operate a 

system for a year or so and then discover 

it? I thought not. 

• Periodically, ensure that the operational 

system still remains validated. 

This will be a planned and scheduled 

activity and will be carried 

out on a regular basis for each computerized 

system in the laboratory 

while it is operational. There may be 

occasions when the review schedule 

is changed to link to a planned upgrade 

of the system, but this is typically 

performed after the system has 

gone live and is in operation.

Pharmaceutical Surveillance with 

Multiple Distributed Portable 

Raman Spectrometers 

LIVE WEBCAST: TUESDAY, SEPTEMBER 27, 2011 AT 2:00 PM EDT 

Register Free at 

http://spectroscopyonline.com/surveillance 

Event Overview 

Globalization of the pharmaceutical supply chain appears to be 

increasing the risk that pharmaceutical consumers will be exposed 

to drug products that have been adulterated. Traditional 

surveillance testing by collecting samples and sending them to 

labs for analysis is inefficient and time consuming. Higher efficiencies 

can be achieved by screening pharmaceuticals at site in order 

to selectively sample and further test suspect materials. Portable 

spectroscopic instruments are now readily available to support 

field testing of pharmaceutical materials. Methods developed on 

these instruments must be rapid and have the sensitivity required 

to identify contaminants in pharmaceutical materials. They must 

also have user friendly interfaces, because field analysis is often 

performed by personnel who are not instrument specialists. Finally, 

efficient procedures for method distribution must be developed 

so that calibration models need not be recreated on each 

individual instrument. This presentation will describe our development 

of portable Raman spectrometric methods for field analysis 

of diethylene glycol in glycerin. The measurements are rapid, requiring 

less than 1 minute per sample, and chemometric methods 

of analysis provide the sensitivity required to detect diethylene 

glycol at levels anticipated when adulteration is economically motivated. 

The calibration transfer procedures utilized to distribute 

these methods to multiple instruments will also be described, and 

the sensitivity of the transferred methods will be compared to the 

sensitivity of methods developed on individual instruments. 

Who Should Attend: 

• Spectroscopists developing practical Raman 

quantitative methods on multiple instruments. 

• Spectroscopists interested in transferring 

methods between instruments. 

For questions, contact Jamie Carpenter at 

jcarpenter@advanstar.com 

Key Learning Objectives: 

• Describe the challenges associated 

with pharmaceutical surveillance using 

portable, geographically distributed 

spectrometric instruments. 

• Describe why quantitative 

chemometric models are often 

necessary for identifying adulterated 

pharmaceutical materials. 

• Describe the advantages of transferring 

calibration models using standardization 

procedures rather than developing 

global calibration models or instrumentspecific 

calibration models. 

PRESENTERS: 

MODERATOR: 

Presented by: 

Sponsored by: 

John Kauffman 

Research Chemist, FDA Division 

Pharmaceutical Analysis 

Connie Ruzicka 

Research Chemist, Division of 

Pharmaceutical Analysis 

Food and Drug Administration 

Laura Bush 

Editorial Director 

Spectroscopy


MORE THAN A CATALOG 

WE MAKE 

IT. 

Edmund Optics ® 

manufactures over 

5 million optics every year 

at its GLOBAL FACILITIES. 

WE DESIGN. 

WE MANUFACTURE. 

WE DELIVER. 

HOW CAN WE HELP YOU? 

Contact our Sales Department 

today for a quote! 

more optics | more technology | more service 

USA: +1-856-547-3488 ASIA: +65 6273 6644 

EUROPE: +44 (0) 1904 788600 JAPAN: +81-3-5800-4751 

www.edmundoptics.com 

• Before an inspection. Occasionally 

some companies may review a system 

before an inspection to ensure 

that there are no major compliance 

issues. However, if this approach is 

taken, ensure that the time between 

the audit and the inspection is sufficient 

to ensure that the remedial 

activities are implemented and work 

before the inspection. Personally, I 

believe that if a computerized system 

is truly critical it will be reviewed on 

a frequency that does not require a 

special review like this. 

• When a system is retired and the data 

are migrated. I will not discuss this 

topic further in these two columns. 

Although you can conduct a periodic 

review at these times during the lifetime 

of a spectrometer system, the principles 

of what a review consists of and 

the way one is conducted are the same. 

Health Warning: 

Periodic Reviews Only Sample 

Periodic reviews and audits should 

carry a health warning. It is important 

to realize that all reviews and audits are 

sampling exercises. The reviewer will 

select the procedures, documents, or 

records to examine and draw conclusions 

based on them that are applicable 

to the whole process being examined. 

Therefore, it is important to realize 

that noncompliances may exist where 

none have been found and reported, 

simply because the sample taken by the 

reviewer did not contain any problems. 

Trained reviewers and auditors know 

this and will inform the process owner 

of this, especially at the end of the review 

and also in the report. This is also 

known by GLP and GMP inspectors, 

and the FDA puts virtually the same 

text into all warning letters to deserving 

organizations: 

The deviations detailed in this letter 

are not intended to be an all-inclusive 

statement of deviations that exist at 

your facility. You are responsible for investigating 

and determining the causes 

of the deviations identified above and 

for preventing their recurrence and the 

occurrence of other deviations. 

There are two points to note: First, 

the specific statement indicating that the 

inspection is a sampling process and that 

the list of deviations from the regulations 

is never complete and cannot ever be 

unless the whole laboratory is reviewed. 

Second, and most important, is that the 

users, laboratory management, and quality 

assurance have the responsibility for 

ensuring regulatory compliance. If you 

find a problem, it is your job, and not that 

of QA or the inspectorate, to resolve it. 

Therefore, if you want to hide behind 

a clean periodic review report, but know 

that noncompliant working practices 

are going on that the reviewer has not 

picked up on them, you are deceiving 

yourself. Moreover, it means that if an 

inspector identifies a problem, especially 

one that you have known of and 

done nothing about, it means that the 

subsequent corrective action will be 

more stringent than if you had found 

the problem yourself and fixed it under 

your terms. It is better for you to have 

found the problem and be in the process 

of fixing it, rather than for an inspector 

to find it, as it demonstrates that 

you are doing your job responsibly and 

diligently. 

Slicing and Dicing: 

Defining the System Scope 

It is important to get the scope of the 

audit correct and not to miss anything 

that could be significant in an inspection 

or could lead to questioning the 

quality of the results generated by the 

system (for example, unvalidated or 

incorrect calculations). Figure 2 shows 

an example of a computerized system 

used for quantitative bioanalysis in a 

GLP-regulated laboratory. The system 

consists of three high performance liquid 

chromatography (HPLC) systems 

with mass spectrometry (MS) detectors; 

each instrument has the MS software 

installed on a workstation to control the 

instrument and then acquire and interpret 

the chromatograms. Data are acquired 

directly to a central server that is 

supported by the IT department. In addition, 

there is a single workstation used 

by analysts to interpret chromatograms 

and relieve congestion on the instruments 

themselves for processing data. 

The question is, How should a periodic 

review be scoped? From Figure 

2 we can see that the system scope



can be broken down into two parts. 

The breadth of the scope could include 

the portion of the system in the 

laboratory and the portion operated 

by the IT department. So the breadth 

of the audit needs to be decided: just 

the laboratory, just IT, or the whole 

system? As an aside, if the system had 

a server that is operated and maintained 

by the laboratory, then the 

whole system scope is the responsibility 

of the laboratory. 

Then we need to determine the depth 

of the scope and determine how far to go 

reviewing the instrument and software 

aspects of the system. In the situation 

shown in Figure 2, each workstation has 

a separate installation of the MS software. 

Therefore, does the review take a 

sample from a single workstation and 

the attached instrumentation? From 

two, or all three installations? This is 

where risk management comes in. As 

the architecture of the overall system relies 

on three individual instances of the 

MS software that have to be set up (for 

example, users, access privileges, and 

software configuration) independently, 

do you want to know if the software 

instances are the same or not? How do 

you know that the three are the same? 

Although the installation and configuration 

documentation may say they are 

the same, has anything changed since 

then on one or more of the software 

instances? So, the depth of the review 

can depend on the technical aspects of 

the system — for example, individual 

installations of software with multiple 

software configurations versus a client 

server architecture where there is just 

a single configuration. Do not forget 

the data processing workstation as well, 

because it will be another individual 

installation and software configuration 

to consider. 

Expressing a personal view, I would 

have a wide system breadth that 

would include both laboratory and 

IT aspects. The depth depends on the 

time available; in the case of Figure 2, 

I would review all instances to ensure 

equivalence, both on paper and in the 

software, but, again, this is dependent 

on the time available. 

What is not shown in Figure 2 is 

whether the system has additional 

installations of the software for validation 

and training. When these are 

present, then the periodic review also 

needs to check them to see that they 

are correctly set up and equivalent to 

the operational system. 

Also, consider an alternative to the 

system configuration in Figure 2: If the 

three systems were standalone with no 

reprocessing workstation, then the periodic 

review could cover three independent 

standalone systems. In this case, 

one aim of the review would be to demonstrate 

that the systems were equivalent 

and that similar results would be 

obtained from any one of them. 

Types of Periodic Review 

Ok, we now have the scope of the 

audit defined in terms of breadth and 

depth; what we now have to decide 

is how we will approach the review. 

There are three basic ways you could 

conduct a periodic review or audit, 

shown in Figure 3. These include the 

horizontal, vertical, and diagonal approaches: 

• Horizontal audit or review: A horizontal 

review is conducted across the 

breadth of the system documentation; 

it attempts to cover all areas but at a 

low depth. It is typically undertaken if 

there is little time available to perform 

the review or if the system has not 

been reviewed before. The aim of this 

type of review is to give the confidence 

that all the major computer validation 

requisites are in place, but there may 

not be enough time to look in depth 

at how the various areas integrate 

together. Note that a horizontal audit 

can turn into a vertical audit if a problem 

is found during the review and 

the problem is required to be investigated 

in more detail. 

• Vertical audit or review: In contrast 

to a horizontal audit, a vertical 

audit takes a very narrow perspective, 

selecting one or more areas 

to review and then going into a 

lot of detail, for instance checking 

that the controlling procedure 

has been followed. As an example, 

a vertical review could look at the 

change control procedure, and all 

the change requests for a specific 

system could be examined in much 

SPECTROSCOPY OF 

MICROSCOPIC SAMPLES 

CRAIC Technologies innovative 

microspectrophotometers provide you 

with UV-visible-NIR analysis of micron 

sized sample areas by absorbance, 

reflectance, fluorescence and lumi- 

nescence spectroscopy, all yielding 

unsurpassed results precision you 

need– rapidly and accurately. 

Capabilities also include film thickness 

measurements, colorimetry and high 

resolution imaging in the UV, visible and 

NIR regions. CRAIC Technologies – 

Perfect Vision for Science . 

Call today, 

+1-310-573-8180 

or visit 

www.microspectra.com 

©2010 CRAIC Technologies, Inc. San Dimas, California (USA).


more detail than possible with a 

horizontal audit. 

• Diagonal audit or review: As the 

name suggests, a diagonal review 

is a mixture of the horizontal and 

vertical audits. The purpose is 

to see that all the major validation 

elements are in place, operate 

correctly, and that all applicable 

processes work and are integrated 

together. Therefore, when examining 

the defining user requirements 

in the horizontal portion of a review, 

the diagonal audit will assess 

the traceability of requirements 

from the uniform reporting system 

(URS) to the rest of the life-cycle 

documents. In addition, the review 

can also take a test script and trace 

it back to the URS. As you can see, 

the diagonal audit examines the 

system more thoroughly than a 

horizontal audit. 

In practice, all three types of auditing 

can be used effectively during a periodic 

review, depending on how much 

Fast-gated ICCD solutions 

The new iStar 

Intensified CCDs 

The new USB iStar from Andor 

Technology stands for a unique 

combination of Speed, 

Sensitivity, Resolution and 

Versatility. 

The iStar platform offers high 

resolution sensors and UV-Vis- 

NIR photocathodes, low-noise, 

high-speed electronics and a 

feature-packed, ultra-low jitter, fully 

integrated and software controlled 

Digital Delay Generator (DDG). 

New 

The ONLY ICCD platform to offer: 

• USB 2.0 

• 5 MHz readout - acquisition rate 

in excess of 48,700 Hz (Burst) 

or 3,570 spec/s (Continuous) 

• 500 kHz sustained gating rate 

• -40 °C TE cooling 

• Gating speeds < 2 ns 

• New generation of on-board 

DDG 

• High QE Gen 2 and Gen 3 

photocathodes 

www.andor.com/istar 

time there is available. 

As mentioned above, a horizontal 

review can turn into a vertical one. For 

example, during a horizontal review of 

change control, the reviewer may ask 

to see three change requests selected at 

random from the list of change control 

requests; note the sampling process 

in the request. When examined and 

compared with the procedure, it may 

be found that two out of three requests 

did not follow the correct procedure. 

So the reviewer asks for three additional 

requests, again selected by 

the reviewer at random. When examined, 

two comply with the SOP 

and one does not. The reviewer now 

has a situation in which six change 

control requests have been reviewed 

and half comply with the procedure 

but, more worryingly, half do not. So 

what should the reviewer do? One 

alternative is to leave the change control 

process and complete the audit. 

The second is to dig further into the 

change control requests and the procedure 

to find out what is the true 

picture and leave the rest of the audit 

until the problem is investigated further. 

Because change control is such a 

vital mechanism for ensuring continued 

validation status, the archaeological 

excavation of the change control 

records should take precedence over 

the rest of the audit, in my opinion. 

Also, consider that there might be a 

systematic issue with change control 

that could affect all computerized 

systems in the laboratory. Therefore, 

the horizontal review turns into a 

vertical audit to discover how deep the 

problem goes: Has it been a consistent 

problem since the last review or has 

the problem only recently started? 

Writing the Periodic Review Plan 

Returning to the execution phase outlined 

in Figure 1, let’s look at the various 

tasks in order, starting with writing 

the plan for the periodic review. This 

consists of a number of activities that 

cumulate in the plan: 

• Agree on the date or dates for the review. 

When a system is due to be reviewed, 

the reviewer will contact the 

process owner to agree on dates for 

the review to take place. How long



the review will take depends on the 

size and complexity of the computerized 

system, but typically it takes between 

1–3 days. It is important that 

when dates are agreed on that key 

personnel will be available to discuss 

their specialist subject areas with the 

reviewer; otherwise the benefit of the 

review could be lost and noncompliances 

could be missed due to the 

lack of specialist knowledge. Smaller 

systems can be audited in a day but 

if the IT department needs to be 

included or a larger system is being 

audited, then it is more likely that 

2–3 days will be required. 

• Agree on the scope of the review. The 

reviewer should ask for information 

about the system (if not known already) 

to determine the scope of the 

review. This is particularly important 

for systems for which the laboratory 

and IT each have responsibilities. In 

such cases, the involvement of the two 

departments in the review needs to 

be coordinated. If the IT department 

is outsourced, then the outsourcing 

company needs to be contacted to ensure 

staff are available for the review. 

• Write the periodic review plan. A review 

plan is written that contains the 

name of the system to be reviewed, 

agreed dates of the review, the department 

and location where the 

system is sited, and the regulations 

and procedures that the review will 

be based upon (for example GMP or 

GLP regulations and industry guidance 

documents). Included in the 

plan should be a timetable of activities 

of when the reviewer wants to 

discuss specific subjects. This is important 

to inform the laboratory and 

any other staff when their participation 

will be required. It helps them 

plan their own work for the day of 

the audit and avoids people hanging 

around waiting unneccessarily. 

• Approval of the review plan. The periodic 

review plan is a formal document 

that needs to be signed by the 

reviewer as the author and a separate 

person as an approver. Depending 

on the company policies, the process 

owner may also need to sign the plan 

to acknowledge that he or she approves 

it and also to implement any 

corrective actions if there are any 

findings or noncompliances. 

Preparation for a Periodic Review 

What, I need to prepare for a periodic 

review? Yes! From the perspective of 

the reviewer, the individual needs to 

read up about the system and refresh 

his or her knowledge on any relevant 

SOPs that the system is validated and 

operates under. This means reading 

key documents such as 

• computerized system validation SOPs 

• validation plan for the last full validation 

of the system to be reviewed and 

the corresponding validation summary 

report 

• user requirements specification for 

the current version of software that is 

installed 

• organizational charts 

• list of applicable procedures as a minimum 

and copies of some of the key 

SOPs, if possible, such as change control 

SOP and user SOPs. 

This approach allows the reviewer 

to have an understanding of the 

system and procedures before arriving 

to perform the review and to be 

able to do some research, if required, 

before the review starts, thus saving 

time while on site. A reviewer could 

ask for more documents than listed 

above, but there is always a balance 

between the quantity of material and 

time used to prepare for the review 

and the time on site; personally I 

prefer to prepare using the key documents 

and procedures. 

The spectroscopists who will be subject 

to the audit also need to prepare. At the 

most basic level, tidy up the laboratory 

(you will be surprised how many laboratories 

do not do this). Also, check that all 

documents are current and approved. If 

there are any unapproved or unofficial 

documents, they must be removed from 

desks and offices and destroyed. There 

are also other areas where the laboratory 

can prepare — for example, by reading 

the current procedures and ensuring that 

training records are up to date. 

Activities During 

the Periodic Review 

After the review plan has been written 

and approved and the reviewer 

Your Photonics Partner 

SPECTROMETERS LASERS TOTAL SOLUTIONS 

The Updated 

i-Raman ® 

High Resolution 

TE Cooled Raman 

Spectrometer 

LABORATORY PERFORMANCE 

WITH THE CONVENIENCE OF 

FIELD PORTABILITY 

Now Available! 

BWIQ Chemometrics 

Software For 

Quantitative 

Analysis 

NEW 

830nm 

785nm , 532nm 

Excitation Wavelengths 

NEW 

Deeper TE Cooling for 

Twice the Integration Time 

Patented CleanLaze® Laser Stabilization 

High Throughput F/2 Spectrograph 

Spectral Resolution as Fine as 3cm -1 

Spectral Range from 65cm -1 to 4000 cm -1 

Fiber Optic Probe for Flexible Sampling 

Sampling Stages, Video Microscopes, 

and Cuvette Holders Available 

Learn more! 

Call 1-302-368-7824 

or visit us at 

www.bwtek.com


has prepared for the review, the 

great day dawns and the review 

takes place. As can be seen in Figure 

1, the activities that take place consist 

of the following steps: 

• The opening meeting: This should 

be the shortest part of the periodic 

review, where the reviewer and the 

laboratory and, when appropriate, 

IT and QA staff who will be 

involved with the audit, are introduced 

to each other. The reviewer 

will outline the aims of the review 

along with a request for openness, 

as it is an internal audit designed to 

identify if the system is under control 

and remains validated or not. 

It is important that the head of the 

laboratory attend both the opening 

and closing meetings to see if 

there are any issues to resolve. The 

importance of the laboratory head 

attending must not be underestimated. 

If this key individual is not 

present, it sends a subliminal message 

to all, including the reviewer, 

that the individual has no interest 

in the validation status of the 

computerized systems. I certainly 

would document his or her absence 

in the review report. 

• How do you work around here? 

I mentioned earlier that the person 

conducting a periodic review 

should not have fixed views of 

how a computer validation should 

be conducted, as there are many 

ways to be compliant. The key 

point in a periodic review is to 

keep asking the question, “Is the 

laboratory in control?” To orient 

myself for an audit or periodic 

review, after the opening meeting 

I prefer that the victims, sorry, 

auditees, give a short presentation 

of how validation is conducted in 

this laboratory. This approach is 

very useful as it allows the person 

conducting the periodic review 

(for example, me) to understand 

the terminology used by the laboratory 

and the overall validation 

strategy used for the system under 

review. In the long run, it helps 

to avoid misunderstandings and 

miscommunication between the 

two parties. 

• Carrying out the periodic review. This 

is the heart of the periodic review 

where the last validation, organization, 

staff training records, change control, 

backup, and recovery operation of the 

system and associated procedures, and 

so forth will be assessed. We will look 

at this in more detail in the second 

part of this column. 

• Reviewer’s private meeting. This is 

the time for the person conducting 

the review to look over his or her 

notes and documents provided by 

the laboratory to see if any observations 

are identified as findings or 

noncompliances. Also, some outline 

notes for the closing meeting are 

prepared; these must include all 

major issues to be discussed with the 

process owner and laboratory management 

— the reviewer should not 

omit bad news and then add these 

little gems to the report so that it 

comes as a surprise to the laboratory. 

• Closing meeting. This is where the 

reviewer will inform the laboratory 

staff about initial findings so that 

there will be no surprises when the 

draft report is issued for comment. 

All findings should be based on objective 

evidence, such as noncompliance 

with a procedure or regulation. 

There may be occasions when a difference 

comes down to interpretation 

of regulations. In that case, the 

auditor should seek information in 

industry guidance documents to 

support the finding. 

• Write and approve the periodic review 

report and action plan. At the 

conclusion of the on-site portion of 

the review, the reviewer now has to 

draft the report, which will contain 

what the reviewer saw and the findings 

or noncompliances. Contained 

either in the report or as a separate 

document will be the action plan for 

fixing the noncompliances. 

• Implementing corrective and preventative 

actions. Any findings and 

their associated corrective and or 

preventative action plans are implemented 

and monitored ready for review 

when the system comes due. 

All the activities listed in this section 

will be discussed in more detail 

and the second part of a periodic 

review will be addressed in the next 

“Focus on Quality” column. 

Summary 

In this installment, I have looked at a 

periodic review or evaluation for computerized 

systems. The function is an 

independent audit to confirm that a 

system maintains its validated status 

and to identify any areas of noncompliance. 

In the next installment, I 

will discuss conducting the periodic 

review, who is involved, and reporting 

the observations and findings. 

References 

(1) R.D. McDowall, Spectroscopy 26(4), 

24–33 (2011). 

(2) EU GMP Annex 11, Computerized 

Systems. 

(3) FDA Warning letter, AVEVA Drug Delivery 

Systems, Inc., 21 May 2010. 

(4) EU GMP Chapter 9, Self Inspections. 

(5) Webster’s Dictionary (www.merriamwebster.com/dictionary). 

(6) FDA Guidance for Industry, Computerized 

Systems in Clinical Investigations, 

2007. 

(7) GAMP Guide, version 5, 2008, Appendix 

08, Periodic Reviews. 

(8) GAMP Good Practice Guide: Risk 

Based Approach to Operation of GXP 

Computerized Systems, 2010, Section 

12: Periodic Reviews. 

(9) C. Burgess and R.D. McDowall, QA 

Journal 10, 79–85 (2006). 

(10) R.D. McDowall, Spectroscopy 23(7), 

26–29 (2008). 

R.D. McDowall 

is principal of Mc- 

Dowall Consulting 

and director of R.D. 

McDowall Limited, 

and the editor of 

the “Questions of 

Quality” column for 

LCGC Europe, Spectroscopy’s sister magazine. 

Direct correspondence to: 

spectroscopyedit@advanstar.com 

For more information on 

this topic, please visit: 

www.spectroscopyonline.com/mcdowall

For questions, contact Jamie Carpenter at jcarpenter@advanstar.com 

A Thermo-Electric Cooling 

Approach to SWIR Spectroscopy 

with InGaAs Array Detectors 

LIVE WEBCAST: Thursday, September 29, 2011 at 4:00pm BST, 11:00 am EDT, 8:00 am PDT 

Register free at http://spectroscopyonline.com/swir 

EVENT OVERVIEW: 

Performing low-light Spectroscopy in the Short Wave 

Infrared Region (SWIR) has historically been undertaken 

with Liquid Nitrogen (LN2)-based InGaAs array detectors to 

access the lowest sensor dark current possible. 

This webinar will explore the actual effect of InGaAs array 

cooling on Signal-to-Noise Ratios (SNR) by considering not 

only sensor dark noise, but also sensor Quantum Efficiency 

evolution with temperature and experimental setups black 

body radiation contributions. We will also discuss the suitability 

and advantages of Thermo-Electrically (TE) cooled 

approach to InGaAs sensor technology over LN2 for SWIR 

Spectroscopy, both from a performance and user convenience 

perspective. 

Presenter: 

Antoine Varagnat 

Product Specialist Spectroscopy & Time- 

Resolved 

Andor Technology plc. 

Moderator: 

Laura Bush 

Editorial Director 

Spectroscopy 

Key Learning Objectives: 

n Understanding the true basis 

for CCD and InGaAs detector 

performance assessment (Signal-to- 

Noise Ratio (SNR)) 

n Understanding the effect of InGaAs 

sensor cooling on thermal noise, 

Quantum Efficiency and associated 

SNR 

n Understanding sensor cooling 

requirement versus photon signal 

regime 

Who Should Attend: 

n Researchers and system integrators 

working in the field of Short Wave 

Infrared (SWIR) and Near-Infrared 

(NIR) Spectroscopy 

Presented by 

Sponsored by 

For questions, contact Jamie Carpenter at jcarpenter@advanstar.com


Atomic Perspectives 

Measurement Techniques for 

Mercury: Which Approach Is 


Analytical techniques for measuring mercury include cold vapor atomic absorption spectroscopy, 

cold vapor atomic fluorescence spectroscopy, and direct analysis by thermal decomposition. 

David Pfeil discusses the advantages and disadvantages of the techniques and provides 

tips for choosing the right technique for various situations. 

David Pfeil 

The United States Environmental Protection 

Agency (US EPA) classifies mercury as a persistent, 

bio-accumulative toxin (1), indicating that 

its toxicity does not diminish through decomposition 

or chemical reaction, and that it is absorbed faster 

than it can be excreted. Recently, efforts to minimize 

the release of mercury, and to track its migration when 

released, have demanded more sensitive analytical 

techniques for its measurement. As these techniques 

have become available, regulatory agencies around the 

world have written new analytical methods specifying 

their use. Table I provides a listing of many of the regulatory 

methods that are available for use with today’s 

technologies. 

Let’s take a look at the analytical techniques in 

more detail and then we’ll come back to the question 

of which technique is right for you. 

Cold Vapor Atomic Absorption Spectroscopy 

In many parts of the world, cold vapor atomic absorption 

spectroscopy (CVAAS) is still the most commonly 

used technique for the determination of mercury. 

Hallmarks of this approach include detection limits 

in the single-digit parts-per-trillion (ppt) range, a 

dynamic range of 2–3 orders of magnitude, and an 

abundance of analytical methods that allow for the 

measurement of mercury in almost any sample matrix. 

The technique was introduced in 1968 by Hatch and 

Ott (2) soon after the first available atomic absorption 

spectrometer. Their work described a device for flame 

AA that enabled them to reduce mercuric ions in solution 

to ground state atoms and transport the mercury 

to the optical path of the spectrometer for measurement. 

Thus, cold vapor atomic absorption was born. 

Very quickly CVAAS became the reference technique 

for mercury determinations. Within a few years, the 

US EPA adopted the technique for the determination 

of mercury in water, soil, and fish. Now, almost 

40 years later, CVAAS remains one of the primary 

techniques for mercury analysis and is the reference 

method for monitoring drinking water per the Safe 

Drinking Water Act (3).



While simple, manual systems 

like that described by Hatch and 

Ott are still available today, most 

modern CVAAS instruments are 

more sensitive, automated, smaller, 

faster, and less expensive than 

generic flame spectrometers with 

cold vapor devices attached. Today’s 

CVAAS systems provide detection 

limits of just a few parts per 

trillion, analyze samples in about 

1 min, require very little operator 

interaction, and take up just a couple 

of square feet of bench space. 

Figure 1 provides an overview of a 

cold vapor atomic absorption system. 

With CVAAS instruments a 

peristaltic pump is typically used 

to introduce sample and stannous 

chloride into a gas–liquid separator 

where a stream of pure, dry gas is 

bubbled through the mixture to release 

mercury vapor. The mercury 

is then transported via carrier gas 

through a dryer and then into an 

atomic absorption cell. Mercury 

absorbs 254-nm light in proportion 

to its concentration in the sample. 

Cold Vapor Atomic 

Fluorescence Spectroscopy 

Hallmarks of cold vapor atomic 

fluorescence spectroscopy 

(CVAFS)-based mercury analyzers 

include sub-part-per-trillion 

detection limits and a much wider 

dynamic range than achieved by 

CVAAS; typically 5 orders of magnitude 

for CVAFS versus 2–3 for 

CVAAS. CVAFS instruments are 

available in two configurations; 

one employing simple atomic fluorescence 

and one that employs gold 

amalgamation to preconcentrate 

mercury prior to measurement by 

atomic fluorescence. The detection 

limit via the simple fluorescence 

approach is about 0.2 ppt whereas 

using the preconcentration approach 

with fluorescence detection 

can be as low as 0.02 ppt. The US 

EPA has promulgated methods for 

each of these approaches; Method 

245.7 (4) is for use without preconcentration 

and 1631 (5) is with 

preconcentration. These methods 

were developed to satisfy the need 

Sample 

Argon gas 

Reductant 

Hg lamp 

Pump 

Gas control 

for quantitation at the National 

Recommended Water Quality 

Criteria for mercury (6). These 

criteria are published pursuant to 

Section 304(a) of the Clean Water 

Act (CWA) and provide guidelines 

for states to use in adopting water 

Mix 

Optical cell 

Figure 1: An overview of cold vapor atomic absorption. 

Sample 

Argon gas 

Reductant 

Pump 

Gas control 

Hg lamp 

Mix 

Optical cell 

Dryer 

Gas-liquid separator 

λ Selector 

Gas-liquid separator 

λ Selector 

AA detector 

Dryer 

AF detector 

Figure 2: An overview of cold vapor atomic fluorescence with gold amalgamation. 

Signal 

Valve 

quality standards that ensure ambient 

waters are safe to fish in, and 

subsequently, that fish are safe for 

consumption. Additional information 

on this subject is available at: 

http://water.epa.gov/scitech/swguidance/standards/current/index.cfm. 

A u 

t rap 

Signal

Whether you’re looking for improved performance, 

versatility or simplicity in your instruments, PerkinElmer 

has once again raised the bar to meet your needs. Inside 

this guide, you’ll find new answers to your process 

challenges, time-saving solutions for your laboratory, and 

next-generation innovations to help you achieve even 

greater success in the years ahead. 

AA | ICP-OES | ICP-MS 

Your Guide to the Latest Advances in Atomic Spectroscopy.

Perfectly Suited To Te Challenges Ahead 

As the recognized world leader in inorganic elemental analysis, PerkinElmer offers a full line of cutting-edge 

instruments for AA, ICP-OES, and ICP-MS. We continue to invest significantly in R&D to pioneer innovations that 

improve your workflow without compromising performance. 

PerkinElmer’s leadership pedigree is built upon a history of technological innovation. And today we’re continuing 

that tradition with an array of breakthrough solutions, including: 

U The space-saving, stacked design of the PinAAcle AA series. 

U The innovative eNeb sample introduction and Flat Plate plasma technology of the Optima 8x00 ICP-OES series. 

U The unique Universal Cell Technology of the NexION ® 300 ICP-MS. 

Read on to learn more about these recent technological advancements, and discover how PerkinElmer can help you 

meet your goals with greater ease, efficiency and certainty. 

PinAAcle 900 Atomic Absorption Spectrometers— 

The Best Technology For Your Science, The Right 

Size For Your Laboratory 

With our long history of product innovation and proven 

performance, PerkinElmer is the most trusted name in 

atomic absorption. Today’s PinAAcle AA spectrometers 

extend that reputation with a cutting-edge fiber optic 

system for the best detection limits possible. 

This newly designed light path not only shapes 100% 

of the beam, it also enables the instrument to have the 

smallest footprint of any combined flame/graphite 

furnace AA system on the market. 

PinAAcle continues PerkinElmer’s pioneering position of 

offering flame, furnace, flow injection, FIAS-furnace and 

mercury/hydride capabilities on a single instrument. The 

spectrometers are available in flame only, furnace only 

and flexible dual-mode models featuring a burner 

assembly above the graphite furnace. With this spacesaving 

stacked design, the PinAAcle 900H and 900T 

AAs are the perfect fit—quite literally—for laboratories 

with wide-ranging requirements but limited space. 

PinAAcle’s graphite furnace models (900Z, 900H, 900T) 

are a cost-effective solution for labs with less demanding 

throughput but greater sensitivity requirements. 

Customers can choose between a traditional HGA with 

deuterium background correction design or THGA 

with longitudinal Zeeman background correction 

design. Common applications include blood-lead 

monitoring and food labeling. To enhance the capabilities 

of our instruments, PerkinElmer offers a full range of 

high-quality graphite products to ensure unparalleled 

performance and reproducibility. 

PinAAcle flame AA systems (900F, 900H, 900T) feature 

a true double-beam design for fast start-up and longterm 

stability without recalibration, ideal for fast-paced 

laboratories analyzing large numbers of samples for 

a limited number of elements. 

Our TubeView color furnace 

camera simplifies autosampler 

tip alignment and sample 

dispensing. 

PinAAcle graphite furnace systems feature our TubeView 

color furnace camera, and every instrument in the family 

offers a versatile 8-lamp housing compatible with our 

Lumina Hollow Cathode Lamps that allow automatic 

setup, or our Electrodeless Discharge Lamps for unmatched 

linearity, sensitivity and precision. 

Other consumables and accessories include sample 

preparation systems, nebulizers, burner heads, PerkinElmer 

Pure Standards, FIAS and mercury/hydride systems, and 

our S10 Autosampler that turns your instrument into a fully 

automated workstation.

©2011 PerkinElmer, Inc. 400214_02. All rights reserved. PerkinElmer ® is a registered trademark of PerkinElmer, Inc. All other trademarks are the property of their respective owners. 

PinAAcle AA Spectrometers 

Discover The PinAAcle Of Performance In AA. Engineered around cuting-edge Tber-optic technology for enhanced 

light throughput and superior detection limits, the new PinAAcle series is the latest innovation from the world leader 

in atomic absorption. Available in flame, furnace, or combination models, PinAAcle instruments offer exactly the level 

of performance you need with the smallest footprint of any combined flame/graphite furnace AA system on the market. 

Experience peak performance and unmatched productivity. Step up to the PinAAcle 

series from PerkinElmer. 

Request your PinAAcle welcome pack—www.perkinelmer.com/pinaaclewelcome

Optima 8x00 Series ICP Optical Emission 

Spectrometers—Eye-Opening Innovations For 

Unsurpassed Performance 

Continuing PerkinElmer’s long tradition of excellence in ICP 

technology, the Optima 8x00 series delivers a level of stability 

and detection limits never before seen in an ICP instrument. 

This breakthrough performance is the result of a series of 

cutting-edge designs and technologies that optimize sample 

introduction, enhance plasma stability, simplify method 

development and dramatically reduce operating costs. 

Our new eNeb electronic nebulizer is the most efficient 

and consistent sample introduction system available. By 

generating a constant flow of uniform droplets, the eNeb 

option optimizes trace element analysis—with detection limits 

2-4x better than those attainable with other systems—to 

facilitate compliance across a broad range of segments, from 

pharmaceutical and food safety to environmental testing. 

Our patented eNeb electronic nebulizer provides a 

constant tow of uniform droplets. 

Another innovation that delivers reduced operating costs is 

our new Flat Plate plasma technology, which replaces 

traditional helical load coils with maintenance-free plasma 

induction plates. This technological advancement reduces 

argon consumption by up to 50% while generating the same, 

robust, matrix-tolerant plasma. 

With its optimized sample introduction and cost-efficient 

operation, the Optima 8x00 series is ideal for laboratories 

analyzing multiple elements in a wide range of samples. It’s 

also a great solution for laboratories needing exceptional 

throughput when analyzing complex matrices with varying 

levels of dissolved solids. 

A patented RF generator featuring maintenance-free 

plasma induction plates replaces traditional helical 

load coils. 

One feature that will literally change your view of ICP-OES is 

our PlasmaCam viewing camera that provides a continuous 

view of the plasma, simplifying method development and 

enabling remote diagnostic capabilities for maximum uptime. 

The Optima 8x00 series also features patented dual viewing 

of the plasma, so elements with high and low concentrations 

can be measured in the same run, improving productivity in 

such areas as food analysis and nutritional labeling. 

To complement all of its hardware innovations, the Optima 8x00 

series features an equally impressive array of enhancements to 

its WinLab32 software, from improved ease-of-use to added 

security, making it ideal for pharmaceutical and nutritional 

testing labs. 

To further enhance your instrument’s functionality, PerkinElmer 

offers a wide range of consumables and accessories, including 

our S10 Autosampler that can easily turn your Optima ICP-OES 

into a fully automated workstation. 

Te PlasmaCam integrated color camera enables 

continuous viewing of the plasma for simpler method 

development and remote diagnostics.


Optima 8x00 Series 

Open Your Eyes To The Revolutionary New Optima 8x00 Series. From the eNeb electronic nebulizertthat generates 

a constant flow of uniform droplets for superior stability and unsurpassed detection limitstto maintenance-free Flat Plate 

plasma technology that uses half the argon of traditional systems, the Optima 8x00 series features a range of breakthrough 

technologies that optimize sample introduction, enhance plasma stability, simplify method development, and dramatically 

reduce operating costs. fie Optima 8x00 series. Discover a level of performance 

never before seen in an ICP instrument. 

Request your Optima welcome pack—www.perkinelmer.com/optimawelcome

NexION 300 ICP-MS—Get Where You Want To Go 

With Three Modes Of Operation 

Engineered to deliver a level of stability, flexibility and 

performance never before seen in an ICP-MS instrument, 

the NexION 300 represents the first truly significant 

industry advancement in recent memory. For the first time 

ever, a single ICP-MS instrument offers both the simplicity 

and convenience of a collision cell and the exceptional 

detection limits of a true reaction cell. 

With its patented Universal Cell Technology (UCT), 

analysts can now choose the most appropriate technique 

for their sample or application. No restrictions on which 

gases can be used. No limits on mass range. No 

compromises on how to work. And no hassles in 

switching from mode to mode. 

The unique Quadrupole Ion Deflector turns ions 

90 degrees, focusing those of a specified mass into the 

universal cell and discarding all neutral species, thereby 

enhancing sensitivity while keeping the cell clean. The 

precise alignment of the deflector and ion beam with 

the Triple Cone Interface further aids in the prevention 

of drift and sample deposition. 

Positively 

Charged Ions 

Un-ionized Material 

In reaction mode, the NexION 300 provides ultimate 

detection limits, even with the most difficult elements or 

matrices. Interferences are removed with little or no loss 

of analyte sensitivity, making the instrument ideal for 

biomedical analysis for human health monitoring. 

In collision mode, a simple non-reactive gas is introduced 

into the cell to remove interferences and deliver better 

detection limits than standard mode. It is ideal for 

routine applications such as those found in food testing 

or environmental laboratories. 

But improved versatility is just one of the benefits you’ll 

enjoy with the NexION 300 series. Thanks to a new Triple 

Cone Interface and Quadrupole Ion Deflector, NexION 

tightly focuses the ion beam, dramatically reducing drift 

and delivering exceptional signal stability hour after hour. 

The new design ensures that ions and neutrals never 

impact the surfaces, eliminating cleaning requirements. 

Add to this our many other accessories and consumables, 

from autosamplers and mercury analyzers to sample 

preparation, spray chambers and standards, and there’s 

no question PerkinElmer offers the most comprehensive, 

trustworthy solutions in ICP-MS. 

In addition to the sampler and skimmer cones, the NexION 300 

features a unique hyper-skimmer cone for the most tightly defined 

ion beam available.


NexION 300 ICP-MS 

The NexION 300 ICP-MS: Three Modes Of Operation. One High-Performance Instrument. Nothing keeps 

your laboratory moving forward like the revolutionary NexION® 300 ICP-MS. With three modes of operation (Standard, 

Collision and Reaction), it’s the only instrument of its kind that can adapt as your samples, analytical needs or data 

requirements change. Experience unparalleled texibility. Enjoy unsurpassed stability. Optimize your detection limits 

and analysis times. fie NexION 300 ICP-MS. Choose the simplest, most 

cost-eflcient path from sample to results. 

See the NexION at PerkinElmer's Gateway—www.perkinelmer.com/gateway

Gearing Up For Your Specific Application 

PerkinElmer’s atomic spectroscopy instruments are designed 

for a wide range of applications. We’re the name behind 

the leading labs in environmental, food/product safety, 

pharmaceutical/nutraceutical, petrochemical and clinical testing 

the world over. To help you assemble the perfect solution for 

your application, we offer a variety of helpful resources. 

A good place to start is the PerkinElmer Gateway. This online 

community and educational resource includes a library of 

application notes as well as industry-specific webcasts, live 

chat in our Scientists’ Cafe, and our virtual Technology Expo. 

Check it out at: www.perkinelmer.com/gateway. 

For your convenience, PerkinElmer also offers a selection 

of application packs. These helpful kits bundle 

appropriate consumables and documentation used to 

optimize a variety of application-specific analyses. It’s 

all part of our comprehensive approach to helping you 

do your best work, year after year. 

Te Winning Combination To Optimize Your Laboratory 

Your instruments are only as good as the components you add to them, as well as the care and attention you give 

them. That’s why PerkinElmer places so much emphasis on delivering only the highest quality consumables, 

accessories, customer service and technical support. 

Based on over 50 years of experience in atomic spectroscopy, we understand your applications, methodologies and 

challenges. We also know that one size does not fit all. That’s why we offer the broadest range of high-end 

consumables and accessories in the industry, from sample preparation and introduction systems to PerkinElmer Pure 

Standards. It’s also why we offer customizable training courses and service plans that meet your exact specifications, 

from compliance through maintenance. 

With over 1,500 trained and certified engineers and service personnel around the world, our OneSource ® Laboratory 

Services offer the most complete portfolio of services in the industry, including complete care programs for virtually 

every technology and manufacturer. This allows you to consolidate all your service contracts under one reliable 

supplier, and to take advantage of responsive, expert technical support—everything you need to ensure your 

instrumentation and your lab are running at optimum levels at all times. 

From our full line of industry-leading instruments, consumables and accessories to the world’s largest and most 

trusted service network, we’re proud to be the one you can count on by every measure. 

PerkinElmer, Inc. 

940 Winter Street 

Waltham, MA 02451 USA 

P: (800) 762-4000 or 

(+1) 203-925-4602 

www.perkinelmer.com 

For a complete listing of our global offices, visit www.perkinelmer.com/ContactUs 

Copyright ©2011, PerkinElmer, Inc. All rights reserved. PerkinElmer ® is a registered trademark of PerkinElmer, Inc. All other trademarks are the property of their respective owners. 

400231_01


Table I: Commonly used regulatory methods 

Cold Vapor Atomic Absorption (CVAAS) 

Cold Vapor Atomic Fluorescence (CVAFS) 

Direct Analysis or 

Thermal Decomposition 

EPA 245.1 EPA 245.7 EPA 7473 

EPA 245.5 EPA 1631 ASTM 6722-01 

SM 3112B 

EPA 7470 

EN13506 

EN12338 

EPA 7471 ISO 17852:2008 

EN1483 

EN13806 

O 2 

Hg lamp 

Sample 

Gas control 

Optical cell 

With CVAFS instruments a 

peristaltic pump is typically used 

to introduce sample and stannous 

chloride into a gas–liquid separator 

where a stream of pure, dry 

gas (typically argon) is bubbled 

through the mixture to release 

mercury vapor. The mercury is 

then transported in the carrier gas 

through a dryer and then either 

directly to the fluorescence cell 

or to the preconcentration trap 

and then onto the fluorescence 

cell. With fluorescence the drying 

stage is quite important as water 

vapor and other molecular species 

can interfere with the fluorescence 

measurement. Once in the 

detector, mercury vapor absorbs 

Fan 

Decomposition furnace 

50-900 o C 

High sensitivity 

λ Selector 

Low sensitivity 

Fan 

AA detector 

Figure 3: An overview of direct analysis using thermal decomposition. 

Catalyst furnace 

600 o C 

Signal 

Dryer 

Amalgam furnace 

254-nm light and fluoresces at the 

same wavelength. Measurement of 

the fluorescence signal is usually 

made at 90° to the incident beam 

to minimize scattering from the 

excitation source. The intensity 

of the fluoresced light is directly 

proportional to the concentration 

of mercury. 

The concentration of standards 

and samples with this technique 

are typically 100–1000× lower 

than those used with CVAAS, 

demanding much cleaner reagents. 

To ensure reagents are low in 

mercury, methods such as EPA 

Method 1631 describe techniques 

to remove mercury from salts and 

some solutions. 

Direct Analysis by 

Thermal Decomposition 

Hallmarks of the direct analysis approach 

include elimination of the 

sample digestion step, fast analysis 

times, and a detection limit of 

about 0.005 ng. Eliminating digestions 

means solid samples can typically 

be run in their native form. 

For laboratories that analyze large 

numbers of solid samples, or that 

would simply rather not perform 

the digestion typically associated 

with CVAAS and CVAFS, direct 

analysis may be ideal. It is worth 

noting that this approach also carries 

with it the benefit of generating 

less acid waste than the solutionbased 

techniques. However, direct 

analysis is not well suited for a 

laboratory whose need is to run 

large numbers of samples already in 

aqueous solution. For liquid sample 

analysis, the detection limit available 

using direct analysis is not 

typically comparable with those of 

CVAAS or CVAFS. This is primarily 

because of the relatively small 

liquid volumes that are processed 

using direct analysis; typically less 

than 1 mL per sample. Consider, 

for example, that the total mercury 

in 1 mL of a sample that contains 5 

ppt (ng/L) of mercury is only 0.005 

ng — this is right at the detection 

limit for direct analysis. In contrast, 

5 ppt is a concentration that 

is trivial to measure by CVAFS. 

However, with solid samples the 

sensitivity difference is quite small 

since the digestion required to put 

the sample into solution introduces 

a significant dilution.



Figure 3 shows an overview of 

the direct analysis technique. With 

this approach, a weighed sample 

is introduced into the decomposition 

furnace with oxygen (or 

air) flowing over the sample. The 

furnace temperature is ramped in 

two stages; first to dry the sample 

and then to decompose it. As the 

evolved gases are released, they are 

carried into a catalyst where further 

decomposition occurs and elemental 

mercury is released. When 

the gas stream leaves the catalyst 

elemental mercury is captured on 

the surfaces of a gold amalgamation 

trap. After the sample’s mercury 

has been collected, the gold 

trap is heated and the accumulated 

mercury proceeds to an atomic absorption 

detector for quantitation. 

ICP or ICP-MS 

Although some analysts prefer to 

utilize inductively coupled plasma 

mass spectrometry (ICP-MS) for the 

determination of mercury, it does 

involve special sample handling 

including the addition of small 

amounts of gold to the sample to 

expedite baseline recovery. And, 

the cost of such equipment can be 

as much as 3 to 5 times higher than 

dedicated CVAAS or CVAAF systems. 

Note: Although inductively 

coupled plasma optical emission 

spectrometry (ICP-OES) based 

instruments can be used to measure 

mercury, trace level analysis is 

problematic due to poor sensitivity. 

Which Technique Is 


Selecting the right technique really 

depends on your analytical needs. 

For some laboratories, the decision 

will be driven solely by the need to 

comply with a specific regulatory 

method. For example, if your laboratory 

is required to analyze samples 

using EPA method 245.1, then 

you will need to use the technique 

of CVAAS. If you are required to 

follow specific regulatory methods 

you may find Table I helpful. 

If your laboratory is not constrained 

by a regulatory method, 

the driving force for the decision 

will more likely be criteria such as 

• the characteristics of your sample 

matrix (for example, solid or liquid) 

• the detection limits you need to 

reach in that matrix 

• your preferences regarding digesting 

the sample or not 

• your budgetary constraints 

Answering a few simple questions 

will guide you in the direction 

of the technique which is right for 

you. The fundamental question: Is 

your sample a solid or a liquid? 

If your sample is a liquid (for example, 

wastewater or drinking water) 

then you will be best served by one of 

the chemical reduction techniques of 

CVAAS or CVAFS. 

At this point you can let your 

detection limit requirements drive 

your decision; with the knowledge 

that CVAAS will provide a 

detection limit of about 2 ppt and 

CVAFS will provide a detection 

limit of about 0.2 ppt (or as low as 

0.02 ppt with gold amalgamation). 

With that said, unless you have a 

preference for CVAAS, our recommendation 

is that you should consider 

CVAFS. Its superior detection 

limits will allow you to report to 

lower levels and its wider dynamic 

range will be a real time saver from 

the perspective of not having to do 

as many sample dilutions. 

If your sample is a solid, you 

have the choice of digesting the 

sample and then analyzing it by 

CVAAS or CVAFS. Alternatively, 

you may be able to skip the digestion 

step and go with direct analysis 

by thermal decomposition. 

For many laboratories, the simplicity 

of direct analysis is very 

appealing. For laboratories that 

already have digestion procedures 

in place the higher capital cost of 

direct analysis relative to CVAAS 

(or CVAFS), which could be up to 

$10,000, may drive the decision. 

Other factors, such as the sample 

homogeneity or volatility may be 

important considerations as well. 

Because direct analysis is limited 

to a relatively small quantity of 

sample (about 1 g), nonhomogeneous 

samples may be best dealt 

with by digesting a larger quantity 

of sample followed by analysis 

using CVAAS or CVAFS. 

Additional assistance with your 

decision about which mercury analysis 

technique is right for you can 

be found at www.teledyneleemanlabs.com/hg_selector. 

References 

(1) Persistent bioaccumulative and toxic 

chemical program, EPA.gov/pbt. 

(2) W.R. Hatch and W.L. Ott, Anal. Chim. 

Acta 40, 2085–7 (1968). 

(3) Analytical Methods Approved for 

Drinking Water Compliance Monitoring 

of Inorganic Contaminants and 

Other Inorganic Constituents, http:// 

water.epa.gov/scitech/drinkingwa- 

ter/labcert/upload/methods_inor- 

ganic.pdf. 

(4) Method 245.7, Mercury in Water by 

Cold Vapor Atomic Fluorescence 

Spectrometry, Revision 2.0, February 

2005, U.S. Environmental Protection 

Agency. 

(5) Method 1631, Revision E: Mercury in 

Water by Oxidation, Purge and Trap, 

and Cold Vapor Atomic Fluorescence 

Spectrometry, August 2002, U.S. Environmental 

Protection Agency. 

(6) National Recommended Water 

Quality Criteria (4304T), 2009, U.S. 

Environmental Protection Agency, 

(Federal Register: August 5, 1997 

62[150]). 

David Pfeil is an Hg 

product manager 

at Teledyne Leeman 

Labs in Hudson, New 

Hampshire. Direct correspondence 

to: dpfeil@ 

teledyne.com. 

For more information on this topic, 

please visit our homepage at: 

www.spectroscopyonline.com


Spectrometers for Elemental 

Spectrochemical Analysis, Part 

IV: Inductively Coupled Plasma 

Optical Emission Spectrometers 

In this tutorial, we discuss inductively coupled plasma (ICP) spectrometers. The basic modules 

of spectrometer systems already have been discussed in Part I of this series (1). Here, we focus 

on the ICP excitation and sample introduction system. A discussion of some optical configurations 

used in ICP is included. 

Carlos Augusto Coutinho and Volker Thomsen 

The plasma excitation spectrometer is a relative 

newcomer, invented in the 1960s, although commercially 

available units were not sold until the 

late 1970s. The term “plasma” here describes what is 

commonly referred to as the “fourth state of matter;” 

that is, a very hot, ionized gas. Plasma sources are typically 

used for the analysis of liquids, finding their primary 

application in environmental monitoring and 

other areas where samples may be readily available in 

liquid form. Although there are different ways to produce 

these plasmas, by far the most common is the inductively 

coupled plasma (ICP). 

In ICP–optical emission spectroscopy (OES), the 

energy from the high-temperature argon plasma 

(5000−10,000 K) excites the sample atoms. Generally, 

the sample must be in liquid form. 

The Plasma 

A radio-frequency (RF) generator, typically run at either 

27.12 or 40.68 MHz and between 1 and 5 kW, provides 

energy to the argon gas flowing through the quartz 

torch by means of an induction coil or RF coil (Figure 

1). In terms of electronic design, the generators can 

be grouped as either “free run” or “quartz controlled” 

types, with similar overall performances. The former 

keeps the loaded energy transferred to the plasma constant, 

independently of variations in the physical properties 

of the sample aerosol, and the latter keeps the 

plasma frequency constant, controlled by a quartz oscillator, 

even under different aerosol conditions. 

RF power is applied to an air- or water-cooled coil, 

generating a magnetic field that induces electrical currents 

in the matter within the coil, thereby producing 

heat. Argon gas is introduced through the torch and a 

high-voltage spark (typically generated by a Tesla coil) is 

applied, causing the argon atoms to ionize. The free electrons 

provide the conductive matter that allows the flow 

of electrical current, which results in a high-temperature 

gas (plasma). Part of the argon gas flow is swirled in 

such a way as to shape and contain the plasma. 

Gases other than argon can be used to generate 

plasma. However, for analytical purposes, argon is the 

most suitable. It presents the following advantages: 

• It is an inert gas and does not react with the sample 

constituents introduced in the plasma. 

• It has the necessary electron energy to excite most of 

the element lines in the periodic table. 

• It is relatively transparent to the bulk of emitted photons, 

which translates into a linear relationship with 

the atom concentration of the elements in the sample 

(that is, straight line calibration curves). 

• It requires relatively low running costs to cope with 

the high consumption required to keep the plasma 

operative (about 18 L/min).



Torch 

Height above 

load coil (mm) 

Plume 

Temperature 

2000 K 

Plasma 

Emission 

zone 

RF generator 

Ar flows 

RF 

coils 

Figure 1: Schematic diagram of ICP excitation 

source. 

The temperature profile in the 

plasma is shown in Figure 2. The 

injected sample solution undergoes 

multiple transformations along the 

way, as described below. 

• The first step is desolvation, the 

removal of the solvent from the 

droplet, to leave a tiny salt particle, 

which is rapidly vaporized 

25 

20 

15 

Aerosol 

input 

6000 K 

6200 K 

6500 K 

6800 K 

10000 K 

Figure 2: Schematic of the temperature profile 

in ICP plasmas. 

Auxiliary argon 

flow 

Sample aerosol 

flow 

Induction 

coils 

Magnetic 

field 

Quartz 

concentric 

tubes 

Typical flows 

Coolant: 7-20 L/min. 

Auxiliary: 0-3 L/min. 

Aerosol: 0.5-1 L/min. 

Argon coolant 

flow 

Figure 3: Schematic diagram of an ICP torch. 

into a gas of the molecule. This 

occurs at the very bottom of the 

plasma. 

• The second step is atomization, 

where the gaseous molecules are 

further broken down or dissociated 

into their component atoms. 

Consumables 

ETP Detectors 

SGE Authorized Dealer 

Detectors ALWAYS in stock 

for next day delivery 

Sample Introduction 

Inert, quartz and glass nebulizers 

Torches, injectors and spray chambers 

Apex high efficiency inlet system 

Flared and conventional tubing 

Standards 

Inorganic and metallo-organic 

Single and multi-element standards 

ICP/ICP-MS calibration and tune solutions 

Cones 

Free Pt Refurbishing 

Platinum Reclaim 

Ni/Cu Reclaim ☞ [$20/sampler - $10/skimmer] 

Container Recycling 

Agilent 

4500, 7500, 7700 

PerkinElmer 

5000, 6000, 9000 & NexION 

Thermo Fisher Scientific 

PQ2, Excell, X-Series, Element, Neptune 

GBC, MicroMass, Nu and more... 

PerkinElmer NexION 

Accessories 

Metals Digestion 

HotBlock 

AutoBlock 

Autosamplers 

SC autosamplers 

SC-Fast integrated system 

Agilent 7700 

SPECTRON INC 

The Leading ICP-MS Cone Supplier Worldwide 

www.SpectronUS.com 

for ICP Supplies


Table I: Typical detection limits (ppb) for various elements in water, using spectrometers 

with different torch configurations — radial, axial, or axial with an ultrasonic 

nebulizer (USN) 

Element Atomic Number Radial Axial Axial + USN 

Li 3 1.1 0.02 

Be 4 0.05 0.06 0.009 

B 5 0.7 0.25 

Al 13 0.08 0.03 0.015 

P 15 3.3 0.9 

Cl 17 60 100 

V 23 1.2 0.29 0.07 

Cr 24 0.6 0.16 0.06 

Mn 25 0.08 0.02 0.008 

Fe 26 0.4 0.19 0.08 

Co 27 0.68 0.18 0.06 

Ni 28 0.65 0.2 0.11 

Cu 29 1 0.23 0.07 

Zn 30 0.18 0.06 0.03 

As 33 3.1 1.2 0.4 

Se 34 7.7 1.9 0.7 

Ag 47 1.1 0.2 8 

Cd 48 0.21 0.06 0.03 

Sn 50 1.7 0.44 0.25 

Sb 51 4.4 1.4 0.5 

Ba 56 0.14 0.03 

Hg 80 1.2 0.6 

Pb 82 3.4 0.95 0.3 

This occurs just above the desolvation 

zone. 

• The third step, excitation, takes 

place at the plasma’s hottest region, 

around 10,000 K, where the 

electrons of the atoms that constitute 

the sample elements are 

excited by the energy transferred 

from the plasma. The excited electrons 

jump to high energy levels 

within the atoms or leave the atom 

completely, producing ions. The 

electrons of the ions may themselves 

be excited to higher energy 

levels. 

• The fourth step takes place in the 

lower temperature region, called 

the emission zone, from about 

7000 K to 6000 K. Here, the electrons 

return to their ground state, 

or lower energy levels, with a subsequent 

emission of photons with 

discrete characteristic energies. 

The ionic lines of the element will 

be emitted at higher observation 

heights in the plasma. 

• Finally, the recombination step 

occurs in the plume of the plasma, 

where the free electrons and ions 

can recombine to produce neutral 

atoms and molecules. This 

region is responsible for partially 

absorbing the emitted photons 

(self-absorption) and therefore 

must be removed in axial plasma 

viewing spectrometers (see below). 

As noted in reference 2, “Measurements 

in the plasma tail zone with 

pronounced temperature gradients 

are severely affected by interferences 

mainly caused by the formation 

of molecular compounds 

and to the presence of EIEs (easily 

ionizable elements).” 

The Torch 

The ICP torch consists of three 

concentric tubes that allow appropriate 

argon flows to maintain and 

constrain the plasma, as well as delivering 

the sample to the plasma. 

Figure 3 shows a diagram of the ICP 

torch. There are three separate argon 

flows: 

The Coolant Flow: The narrow 

spacing between the outer and middle 

tubes is shaped in such a way as 

to make the argon gas spiral tangentially 

between the tubes as the gas 

rapidly rises. The function of this 

so-called “coolant gas” is to keep the 

walls of the torch cool and to shape 

and constrain the plasma. 

The Auxiliary Flow: The auxiliary, 

or intermediate, flow supports 

the plasma, allowing the whole 

Axial 

Depth of field 

Induction 

coil 

Radial 

Central channel 

Viewing 

volume 

Viewing 

volume 

Central 

channel 

Slit height 

Work coil 

Figure 4: Schematic of the two torch 

configurations. 

plasma to be raised or lowered as 

the flow is increased or decreased. 

By increasing the flow, the distance 

between the bottom of the plasma 

and the tip of the injector tube becomes 

greater. Thus, the heat generated 

at the injector’s tip is reduced, 

minimizing the build-up of salts or 

carbon deposits (organics), which 

may clog the admission of the sample 

solution. 

The Nebulizer Flow: The nebulizer 

flow carries the sample aerosol 

up into the plasma. The narrow 

tip at the end of the injector allows 

the gas to flow at high velocity and 

punch a hole through the plasma. 

Torches may be made from a variety 

of materials, and may be one piece or 

of the demountable type. The outer 

tubes typically are manufactured 

from quartz, and the injector tube 

may be made of quartz or a ceramic 

material if corrosion resistance 

(such as to HF) is required. 

Torches can be manufactured to 

work either in the vertical position 

(radial view) or a horizontal position 

(axial view). See Figure 4. 

The vertical torch, despite its 

smaller analytical viewing volume, 

allows the plasma to be viewed in 

its various regions by a simple adjustment 

of the torch observation



height. This reduces the background 

radiation from the high background 

emission zone just above the induction 

coils. However, since the 

emitted photons produced in the 

most unstable outer regions of the 

plasma also contribute to the total 

emission, the stability of measurement 

is affected and higher RSDs are 

produced. 

Horizontal torches are “viewed” 

by the optics along their entire axis, 

in the central region of the plasma. 

The useful analytical central volume 

region is the most stable region 

within the plasma, as well as the 

least affected by the electromagnetic 

field that generates the plasma. 

Therefore, it produces a more stable 

emission resulting in less noise and, 

as a consequence, better detection 

limits. On average the LODs are 

2–10 times better than those obtained 

with vertical torches (Table 

I). The downside of these torches is 

that the optical system “sees” the entire 

plasma along its axis. Therefore, 

all the emission coming from the 

higher temperature regions of the 

plasma, responsible for the higher 

background noise, are incorporated 

into the resulting emission spectra. 

High molecular order samples, such 

as organic substances, may produce 

a complex spectral background, in 

particular in the UV emission range. 

Also, the use of axially viewed 

torches requires the elimination of 

the plume region of the plasma. This 

region, because of its lower temperature, 

may absorb a great portion of 

the emitted photons, resulting in 

the reduction of the analytical sensitivity 

and production of nonlinear 

calibration curves (self-absorption). 

Finally, because of their operational 

mode, horizontal torches usually 

require more frequent cleaning and 

replacement. 

Although both viewing modes 

can cope with any type of matrix, it 

is generally accepted that horizontal 

torches (axial) perform better 

for very low concentration levels in 

relatively matrix-free sample environments, 

whereas vertical torches 

show better performance in matrices 

Drain 

Torch 

Spray chamber 

where flux agents or a high quantity 

of total dissolved solids (TDS) are 

present and where higher element 

concentrations are expected. Some 

instruments make use of a series 

of mirrors placed around a fixed 

horizontal (axially viewed) torch to 

allow a subsequent radial observation 

of the emitted radiation, thus 

combining both axial and radial 

views in one instrument. 

Sample Introduction System 

Analyses by ICP are usually carried 

out with samples in liquid form, 

although solid and gas forms also 

can be used. In this section we will 

restrict ourselves to liquid samples. 

The introduction of samples in the 

solid and gas states will be discussed 

in the “Special Topics” section 

below. 

The reason for a sample introduction 

system is to deliver a consistent 

flow of sample to the plasma torch 

through an argon flow (Figure 3). 

The aerosol generated to be introduced 

into the plasma consists of 

fine droplets of the aqueous sample. 

Only small droplets of liquid will go 

through these stages reproducibly, 

and so a sample introduction system 

must be capable of providing these. 

Only in this way can quantitative 

analysis be performed. If samples 

Nebulizer 

Figure 5: Schematic of an ICP sample introduction system. 

Peristaltic 

pump 

are injected at different rates into 

the plasma, then results may not be 

comparable. 

How is the liquid sample introduced 

into the plasma? The sample 

introduction system consists of several 

parts, as shown in Figure 5: 

• the peristaltic pump 

• the nebulizer 

• the spray chamber 

• the drain 

The Peristaltic Pump: Liquid 

samples are removed from the sample 

container through a small bore 

(capillary) tube. This is generally 

produced by the action of a peristaltic 

pump, which provides even 

sample delivery. However, the peristaltic 

pump must be of a sufficient 

size and have a suitable number of 

rollers to ensure a constant flow of 

solution, rather than a pumping action. 

The peristaltic tubing (internal 

diameter of tube) also must be 

carefully selected to guarantee the 

appropriate sample delivery rate. It 

also must be chemically inert with 

respect to the liquid being pumped 

through it. 

The Nebulizer: The sample runs 

through the tubing from the peristaltic 

pump until it reaches the 

nebulizer. The purpose of the nebulizer 

is to generate an aerosol that 

can be consistently delivered to the


ICP torch 

Spray chamber 


Babington 

nebulizer 

Argon in 

Figure 6: Introduction system for slurries. 

Aerosol input 

Peristaltic pump 

Electrode 

Figure 7: Spark ablation sample introduction. 

Magnetic stirrer 

Sample 

Ar input 

plasma. There are two basic types of nebulizer used by 

ICP: pneumatic and ultrasonic. These terms merely describe 

the type of force used to break down the liquid 

into an aerosol. 

Pneumatic nebulizers were the first to be used in ICP 

as they were simply an extension of those already in use 

in atomic absorption (AA) spectrometry instrumentation. 

The biggest difference between ICP and AA nebulizers 

is the delivery rate. It is typical for the delivery of 

the gas flow in AA to run at approximately 10 L/min. 

The gas flow rate for the ICP is much lower, generally 

around 1 L/min. More information on nebulizers may 

be found in Appendix I. 

Spray Chamber: The spray chamber connects the 

nebulizer to the torch. The primary function of the 

spray chamber is to remove the larger aerosol droplets 

and only allow the very finest of the droplets, usually 

below 8 μm, to be carried into the plasma. In fact, only 

about 2–3% of the sample volume reaches the plasma. 

Spray chambers vary in design, and include the Scott 

double pass, conical with impact bead, and cyclonic 

types. In each case, the construction of the spray chamber 

is such that it causes the larger drops to impact some 

part of the chamber and be transported to the drain. 

Drain: The drain has two important functions; the 

obvious one is that it removes the excess sample solution 

from the spray chamber to a waste container. The 

second function is to supply the back pressure necessary 

to ensure the nebulizer gas flows through the torch. 

Drains may be either gravity fed with a loop or U-tube 

to provide the necessary back pressure, or be pumped 

through peristaltic tubing. The back pressure should be 

kept constant; otherwise it can change the sample flow 

into the plasma and affect the emission signal. 

Optical System Configurations 

The principles of diffraction and interference, on 

which the various optical arrangements are based, were 

discussed in Part I of this series (1). Some ICP spectrometers 

use an optical configuration other than the 

Paschen-Runge mount (1). Despite the different geometries, 

the optical configurations used in ICP spectrometers 

have the sole function of dispersing the emission 

spectra of the sample generated in the plasma into their 

characteristic spectral lines. 

Types of ICP Optical Configurations: Many different 

types of optical arrangements are commercially available 

for ICP spectrometers. Perhaps the most common 

are the traditional Paschen-Runge mount, the echelle 

configuration, and the Czerny-Turner mount. 

The Paschen-Runge mount benefits from the sensitivity 

provided by the first-order diffraction and its few 

component elements, and can cope either with photomultiplier 

detectors or a multiple series of linear-array 

CCDs arranged along the Rowland Circle. 

The echelle optical configuration produces multiple 

diffraction patterns of higher orders displaced in a format 

specially designed to cope with a two-dimensional 

solid state detector array (CCD). For instruments covering 

wavelengths in the UV region, a specific optic–CCD 

combination is required, avoiding quartz components 

that heavily absorb the UV radiation. 

The use of large-size CCDs with a binning array of 

sensitive pixels, or equipped with traditional photomultiplier 

detectors may require a different type of optical 

arrangement: the Czerny-Turner mount. 

Some ICP spectrometers nowadays make use of more 

than one optical system, mounted in one single optical 

chamber, to improve their performance in specific 

wavelength ranges. 

It is worth mentioning that the emitted photons in the 

UV range are partially or even totally absorbed by the

A Compound-Based Approach to Simplify 

Method Development and Data Processing 

for Multiple Residue Analysis by GC-MS-MS 

LIVE ON-DEMAND WEBCAST: WEBCAST Wednesday, August 17, 2011 at 11:00 AM EDT 

Register Free at 

www.spectroscopyonline.com/compound-based 

Event Overview: 

;andem mass spectrometry coupled to chromatography, such as 

LC-MSMS or GC-MSMS, operated in the multiple reaction monitoring 

(MRM) mode, has become the method of choice for targeted screening 

of multiple residues in complex food matrix samples due to high 

specificity and its ability to monitor many product ions of a large number 

of compounds Regulations have also been established to require 

measurement of multiple MRMs (two or more) for each target analyte, ie, 

quantitation ion (one) and qualified ion(s), thus making it common to run 

several hundreds or even thousands MRMs in one method 

Method development, including both setting up the MRM table for 

data acquisition and assigning each MRM to its target analyte for data 

processing, is complicated and time consuming 0n this study, a greatly 

simplified compound-based approach to MRM method development is 

introduced and demonstrated for analysis of pesticides in vegetables 

after extraction with 8


Additional 

argon 

Gas liquid 

separator 

To ICP 

To drain 

Carrier 

argon 

gas 

Acid 

Figure 8: Schematic of a hydride generator. 

Capillary tubing 

Argon gas inlet 

Mixing 

cells 

NaBH 4 

Sample 

Sample inlet 

• The sample is introduced in the form of a slurry where 

the particles, after being reduced to a small mesh size, 

are mixed with a solvent and kept under continuous 

agitation by means of a magnetic stirrer before their 

introduction in the plasma (Figure 6). 

• Using a more sophisticated sample introduction system, 

such as an electrical spark or laser, tiny particles 

are ablated from the surface of the sample, which are 

then carried in a stream of argon to the plasma (Figure 

7). Because of the complexity of this type of matrix, 

a “robust” plasma condition is required. In the literature, 

a plasma condition is considered “robust” if it is 

capable of supporting the introduction of a complex 

matrix aerosol without significantly changing the 

plasma physical properties. The assessment of such 

a state can be carried out by measuring the intensity 

ratio of two lines, an atomic and an ionic, such as the 

Mg II (280.2 nm)/Mg I (285.2 nm) ratio. A ratio of 

around 10 is said to be an efficient indicator of the 

plasma robustness to cope with complex matrices (3). 

The spark and laser ablation techniques tend to deliver 

the sample in a small discrete amount of time, and 

so the analytical reading must be timed very carefully 

for the actual analysis. 

Introduction of Gases and Vapors: Some hydrideforming 

elements, such as As, Se, and others (Hg, Sb, 

Bi, Ge, Pb, Te, and Sn), can be introduced directly in 

the plasma in the vapor form. This provides detection 

limits in the parts-per-billion and sub-part-per-billion 

range. A hydride-generating sample introduction system 

is shown schematically in Figure 8. 

Figure 9: Schematic of a concentric nebulizer. 

air and moisture environment trapped inside the optical 

bench. Therefore, vacuum or an argon flush in the optical 

chamber is required. As the flushing of a relatively 

large optical chamber may require a longer instrument 

start-up time to completely eliminate all the air and 

moisture, some instruments have their optics factory 

sealed with argon, thus providing faster start-up with 

the additional benefit of no consumption of this gas. 

It is beyond the scope of this tutorial to comment on 

the advantages or disadvantages of each type of optical 

arrangement. However, Appendix II presents some 

guidelines in terms of the following performance characteristics: 

speed of analysis, resolution, stability, sensitivity, 

wavelength coverage, and overall cost. 

Special Topics 

Introduction of Solids: Under special circumstances, 

solid samples also may be analyzed using an ICP instrument. 

This introduction of solid samples typically takes 

one of two forms: 

Summary 

The ICP excitation source provides a powerful addition 

for those involved in optical emission spectrochemical 

analysis. Here, we have discussed the ICP excitation and 

sample introduction system. A discussion of some optical 

configurations used in ICP-OES also has been included. 

The flexibility of this technique to handle various 

types of materials, its ability to detect most of the 

elements in the periodic table over a very wide range of 

concentrations (from parts-per-billion to percent levels), 

and the capability of simultaneous analysis of a large 

number of elements per sample in times below 2 min, 

makes ICP a very important tool in any modern laboratory. 

Appendix I: ICP Nebulizers 

There are three basic designs of pneumatic nebulizers. 

The first of these is the concentric nebulizer. A concentric 

nebulizer typically is made from glass and contains 

a very fine capillary running the length of the nebulizer. 

Concentric nebulizers (Figure 9) are very popular 

because of their excellent stability and sensitivity. The 

biggest drawback is the material that is used to manufacture 

them, which means these nebulizers are fragile 

and cannot be used with solutions containing hydroflu-



Argon inlet 

Liquid sample 


Aerosol 

Liquid sample 

Groove 

Argon 

Figure 11: Schematic of a Babington nebulizer. 

Liquid sample 

inlet 

Figure 10: Schematic of a cross-flow 

nebulizer. 

oric (HF) acid. Also, because of the 

small capillary diameter, they tend 

to clog in the presence of solutions 

with high TDS content. There are 

variations on this type of nebulizer, 

including the microconcentric nebulizer, 

which is manufactured from 

plastic rather than glass and therefore 

does not suffer ill effects from 

the use of HF. However, the sample 

delivery rate is much lower. 

The second main design of pneumatic 

nebulizer is that of the crossflow 

nebulizer (Figure 10). This consists 

of two capillary tubes at right 

angles to each other. A high speed 

flow of argon is forced across the liquid 

stream in the second capillary, 

creating the aerosol. The slightly 

larger capillary tubes in this design 

minimize clogging, which is an advantage 

over the concentric nebulizer, 

thus increasing their capacity 

to handle solutions with up to 20% 

TDS. However, depending on its design, 

the cross-flow may not be as 

efficient in producing the fine droplets 

required for analysis, resulting 

in slightly poorer RSDs as compared 

to the concentric nebulizers. 

The third design of pneumatic 

nebulizer is the Babington nebulizer. 

The sample solution is allowed 

to pour over a surface with a small 

orifice, through which high pressure 

argon is passing. The argon shears 

the liquid into small droplets. Because 

it is only the argon gas that 

passes though the small hole, this 

design is perfect for both viscous 

samples and for samples containing 

high total dissolved solids, as it is 

essentially clog-proof (Figure 11). A 

variation on the Babington is the V- 

groove nebulizer. 

The ultrasonic nebulizer (USN) 

uses the oscillations of a piezoelectric 

transducer to break up the 

sample into the aerosol (Figure 12). 

This type of nebulization is more 

efficient than the previously mentioned 

pneumatic types, so more 

sample gets to the plasma. An important 

limitation of this type of 

nebulizer is its reduced capacity to 

handle high-TDS samples, mainly 

related to its cleaning and memory 

effects. 

Appendix II: Optical System 

Requirements for a Modern 

ICP Spectrometer 

This appendix presents some guidelines 

regarding the following performance 

characteristics: analysis 

speed, resolution, stability, sensitivity, 

wavelength coverage, and overall 

cost. 

Analysis speed: Polychromators, 

fitted with various sensor devices, 

are capable of simultaneously carrying 

out the analysis of multiple 

element lines, thereby drastically 

reducing the overall time required 

to produce a result. The typical analysis 

time for this type of arrangement 

is around 1 min for almost 

an unlimited number of elements. 

Monochromators, on the other 

hand, are capable of doing only one 

or a limited number of elements at 

a time, carrying out their analytical 

task in a sequential mode. Typical 

analysis time in this optical arrangement 

depends on the number of elements 

to be analyzed. On average, 

no more than two to three elements 

per minute are determined, a rather 

long analysis time as compared with 

the immediate response of the simultaneous 

optical arrangements. 

Therefore, the use of sequential 

spectrometers should be considered 

only in laboratories with a limited 

sample throughput, or laboratories 

where the number of elements required 

per sample is small. Note: 

The widespread use of CCDs, replacing 

the traditional photomultipliers, 

has greatly reduced the number of 

commercially available ICP spectrometers 

equipped with a monochromator 

design. 

Resolution: The resolution required 

depends on the spectral complexity 

of the sample matrix. Rare 

earth materials, for example, have 

notoriously complex spectra and an 

optical arrangement designed with 

a high capability of separating adjacent 

spectral lines that is recommended 

to eliminate spectral line 

interferences. That is, an optical system 

with a high “resolving power” is 

required to cope with the problem of 

overlapping, unwanted lines on the 

analytical lines of interest. 

Stability: The more components 

an optical arrangement has, the 

more complex its design and the 

longer the path length from the 

plasma-emitted photons to the detector 

or detectors. In this case, 

rigid thermal control of the optical 

bench may be necessary to prevent 

minute displacements of the optical 

components’ alignment because of 

thermal expansion and contraction.


Heating element 

Transducer 


To 

plasma 

Overall Cost: The combination optical bench–detector 

is the most expensive component of an ICP spectrometer. 

Therefore, “simple” analytical tasks, a situation 

often found in laboratories carrying out straight 

production control analysis of few elements at parts-permillion 

or percent concentration levels, do not necessarily 

require expensive optical devices. For this kind of application, 

many instruments in the range of US$60,000 

are available. 

Readers must carefully balance all the optical performance 

requirements necessary to fulfill their particular 

analytical needs with the benefits brought by each arrangement. 


Sample inlet 

Water 

cooling 

Figure 12: Schematic of an ultrasonic nebulizer. 


Such temperature changes may result in spectral line 

shifts, which are responsible for long-term instrumental 

drift. Clever solutions to this problem have been 

adopted, such as a close monitoring of a reference line 

throughout all the analysis integration time with automatic 

compensation and correction of eventual line 

shifts through a dedicated software mathematical 

model. 

Sensitivity: The more reflective or refractive surfaces 

in the light path of the optical system, the greater the 

attenuation of the beam, reducing overall sensitivity. 

Modern digital sensor devices can partially cope with 

this signal reduction by electronically enhancing the 

threshold peak values, sometimes at the expenses of an 

overall background noise increase. In this type of instrument, 

a background reduction can be achieved by 

Peltier cooling of the detector at temperatures around 

–30 °C, sometimes at the expense of a longer instrument 

start-up time. 

Wavelength Coverage: The greater the wavelength 

range that the optical system covers, the more versatile an 

ICP spectrometer will be. Certain families of elements, 

such as the halogens, only have sensitive lines below 

170 nm. Therefore, if their analysis is required, an optical 

system covering this region is mandatory. However, 

it should be noted that, depending on the optical system 

geometry, greater wavelength coverage may be obtained 

at the expense of instrument resolution. 

References 

(1) V. Thomsen, Spectroscopy 25(1), 46–54 (2010). 

(2) L. Trevizan and J. Nðbrega, J. Braz. Chem. Soc. 18(4), 678–690 

(2007). 

(3) J.M. Mermet and E. Poussel, Applied Spectroscopy, Focal Point 

49(10), 12A–18A (1995). 

Suggestions for Further Reading 

P.W.J.M. Boumans, Ed. Inductively Coupled Plasma 

Emission Spectroscopy – Part I, Methodology, Instrumentation, 

and Performance (John Wiley & Sons, New 

York, 1987). 

P.W.J.M. Boumans, Ed. Inductively Coupled Plasma Emission 

Spectroscopy – Part II, Applications and Fundamentals (John 

Wiley & Sons, New York, 1987). 

P. Gaines, ICP Operation, A Guide for New ICP Users. Online 

at http:// www. ivstandards.com/tech/icp-ops/ 

P. Gaines, Reliable Measurements. Online at 

http://www. ivstandards.com/tech/reliability/ 

A. Montaser and D.W. Golightly, Inductively Coupled Plasmas 

in Analytical Atomic Spectrometry. (VCH, Weinheim, 

Germany, 1992). 

Carlos Augusto Coutinho, a retired senior researcher 

at Usiminas Steelworks R&D Analytical Division, is presently 

a consultant in Brazil. As a hobby, he enjoys reading subjects 

related to anthropology and playing the piano. He can be 

reached at cacoutinho@task.com.br. 

Volker Thomsen, a physicist by training, has some 30 

years of experience in elemental spectrochemical analysis 

(OES and XRF). He is currently a consultant in this area from 

his home in Atibaia, São Paulo, Brazil. His other interests 

include mineralogy and history of science. Occasionally, 

he still plays the blues harmonica. He can be reached at 

vbet1951@uol.com.br. ◾ 

For more information on this topic, please visit our 

homepage at: www.spectroscopyonline.com

2012 

Photonics 

West 

21–26 January 2012 

Register Today 

Applications of optoelectronics, lasers, 

micro/nanophotonics, and biomedical optics 

Location 

The Moscone Center 

San Francisco, California, USA 

spie.org/aboutpw 

Conference dates 

21–26 January 2012 

Exhibition dates 

BiOS: 21–22 January 

Photonics West: 

24–26 January 

Technologies 

- BiOS–Biomedical Optics 

- OPTO–Integrated Optoelectronics 

- LASE–Lasers and Applications 

- MOEMS-MEMS–Micro & Nanofabrication 

- Green Photonics


Product resources 

head_products 

Atomic absorption spectrometer 

text_products The iCE 3300GF text_products atomic 

text_products absorption spectrometer text_products from 

text_products Thermo Fisher text_products 

Scientific is 

text_products designed for dedicated company graphite 

furnace address, analysis website in envi- 

name 

ronmental, academic, clinical, 

and food safety laboratories. 

The instrument includes an 

integrated furnace autosampler 

and reportedly provides 

deuterium background correction and automatic optical setup. Other 

features include an Ebert optical system and a graphite furnace 

vision system. Thermo Fisher Scientific, Inc., Waltham, MA; 

www.thermoscientific.com/ice3300 

head_products 

Diffraction gratings 

text_products Diffraction gratings text_products from 

text_products Optometrics are text_products available for 

text_products wavelengths ranging text_products from UV 

text_products to infrared. According company to name the 

address, company, website its in-house ruling 

capabilities and production 

and development holographic 

laboratories enable customers 

to choose the right grating for 

a given application. Optometrics, Ayer, MA; 

www.optometrics.com 

head_products 

Elemental analysis service 

text_products Evans Analytical text_products Group offers 

text_products materials characterization text_products 

text_products measurement text_products 

support for 

text_products both production company and R&D. The 

name company address, reportedly website can perform 

major, minor, trace, and 

ultratrace elemental analyses 

and helps customers determine 

trace impurities during materials 

development, including the addition 

of dopants and purity certification of raw materials. According to 

the company, material identification and defect or inclusion analysis 

also can be performed on unknown solids from a minute amount of 

material. Evans Analytical Group, Syracuse, NY; www.eaglabs.com 

head_products 

Raman spectrometer 

text_products B&W Tek’s i-Raman text_products thermoelectric-cooled 

text_products Raman 

text_products 

text_products spectrometer text_products 

is available with 

text_products BWIQ chemometrics company software name 

address, for quantitative websiteanalysis. The 

spectrometer reportedly offers 

830-, 785-, and 532-nm 

excitation wavelengths and a 

spectral resolution of 3 cm -1 . 

The instrument also features 

the company’s CleanLaze 

system for laser stabilization. 

B&W Tek, Inc., Newark, DE; www.bwtek.com 

head_products 

Technology handbook 

text_products The Book on the text_products Technologies of 

text_products Polymicro is Polymicro’s text_products guide to 

text_products optical fiber, capillary text_products tubing, and 

text_products related assemblies company and micro-components. 

address, According website to the company, 

name 

the handbook also includes specification 

sheets. Polymicro 

Technologies, a Subsidiary of 

Molex, Phoenix, AZ; 

www.polymicro.com 

head_products 

CCD camera 

text_products Andor’s iStar DH320T text_products intensified 

CCD camera text_products provides 

text_products 

text_products -40 °C thermoelectric text_products cooling, 

low-noise company electronics, name 

text_products 

address, and high website quantum efficiency 

photocathodes. According to 

the company, the device has 

spectral acquisition rates up 

to 38,000 Hz, timing control 

with low-jitter electronics, a 

software control interface, and 

gating of



head_products 

Milling and sieving magazine 

text_products Retsch recently text_products published the 36th 

text_products edition of The text_products 

Sample, the company’s 

biannual text_products customer magazine. 

text_products 

text_products The new edition company focuses on the art 

name of milling address, and includes website application 

examples from areas such as food, 

minerals, environment, and plastics. 

The publication is available for free 

by downloading a PDF from the 

company’s website. Retsch, Inc., 

Newtown, PA; www.retsch-us.com 

head_products 

Mixer–grinder 

text_products The ShakIR ball text_products mill from Pike 

text_products Technologies text_products 

is designed to 

text_products grind and mix text_products 

IR-transparent 

text_products diluents for diffuse company reflectance name 

address, measurements. website According to 

the company, the accessory 

features electronic control and 

a protective shield for safety 

during use. 

Pike Technologies, 

Madison, WI; 


head_products 


text_products The Craic Apollo text_products 


is designed text_products to be 

text_products 

text_products used either in a text_products 

stand-alone 

text_products configuration or company as addition 

name to the company’s address, website UV-visible- 

NIR microspectrophotometer 

to enhance its capabilities with 

Raman microspectroscopy. 

According to the company, the 

self-contained unit features an excitation source, an optical interface to the 

microscope, a Raman spectrometer, and software for instrument control 

and data analysis. Different units reportedly are designed for use with different 

wavelength lasers and can be used in conjunction with one another. 

Craic Technologies, San Dimas, CA; www.microspectra.com 

head_products 

FT-NIR spectrometer 

text_products Bruker Optics’ text_products 

Tango FT-NIR 

text_products spectrometer text_products 

is designed for 

text_products use with liquids text_products or solids with 

text_products an integrated company PC and monitor 

or as website a separate analysis 

name 

address, 

station. According to the 

company, the analyzer can be 

integrated into a network or 

used as a stand-alone system. 

Bruker Optics, Billerica, MA; 

www.brukeroptics.com 

head_products 

FT-IR spectrometer 

text_products The Spectrum text_products 

Two FT-IR spectrometer 

from text_products 


text_products 

text_products is designed to text_products 

perform rapid 

text_products analytical measurements company for 

name unknown address, substance website identification, 

material qualification, and 

concentration determination. 

The spectrometer includes the 

company’s Spectrum Touch 

touch-screen user interface, which is intended for use in applicationspecific 

quality control analysis. According to the company, applications 

include fuel and lubricant analysis, pharmaceutical and nutraceutical 

analysis, environmental and polymer analysis, and the teaching of 

these methods in academic laboratories. PerkinElmer, Inc., 

Seer Green, United Kingdom; www.perkinelmer.com/ftir 

head_products 

High voltage converters 

text_products High voltage converters text_products from 

text_products EMCO High Voltage text_products Corporation 

are designed text_products with a metal 

text_products 

text_products case and a shielded company transformer. 

The website 10-W converters 

name 

address, 

reportedly feature low EMI/ 

RFI, low ripple, short-circuit 

protection, and input–output 

isolation and filtering. According 

to the company, the converters are PCB mountable and require 

no external components. EMCO High Voltage Corporation, 

Sutter Creek, CA; www.emcohighvoltage.com 

head_products 

Inert nebulizer 

text_products The Duramist text_products 

nebulizer 

text_products from Glass Expansion text_products 

text_products is designed to text_products 

be HF 

text_products resistant and to company handle 

name high concentrations address, website of 

dissolved solids. The 

nebulizer, which is made 

of PEEK, reportedly has 

sensitivity and precision comparable to that of the company’s 

concentric glass nebulizer but can be used in ICP-OES 

applications involving HF. Glass Expansion, Inc., 

Pocasset, MA; www.geicp.com 

head_products 

UV–vis spectrophometer 

text_products Agilent’s Cary text_products 

60 UV–vis 

text_products spectrophotometer text_products is 

text_products designed with text_products 

fiber-optics 

text_products capabilities that company allow for name 

address, remote sampling website ranging 

from bulk solutions to cold 

biological samples. According 

to the company, the 

spectrophotometer’s lamp 

typically lasts 10 years. The 

instrument reportedly includes local language software and tutorials 

and has a scan rate of up to 24,000 nm/min. Agilent Technologies, 

Santa Clara, CA; www.agilent.com


IR head_products 

spectrometer 

The text_products 4100 ExoScan text_products mid-IR spectrometer 

text_products from Agilent text_products is a onemodule, 

text_products 6.5-lb text_products 

system for use in 

the text_products laboratory or company onsite. According 

to name the company, address, website the handheld 

system features a choice of interchangeable 

sampling interfaces 

and allows users to choose diffuse, 

grazing angle, specular reflection, 

or spherical ATR sampling interfaces. 

Applications include infrared 

absorbing and scattering surfaces, 

reflective metal surfaces with coatings 

and films, and bulk materials such as powders and granules. 

Agilent Technologies, Santa Clara, CA; www.agilent.com 

Diffuse head_products reflectance accessory 

The text_products DiffusIR diffuse text_products reflectance 

text_products accessory text_products from Pike 

Technologies text_products is text_products designed to 

enable text_products catalytic company research, name 

including address, website investigation of 

reaction pathways and 

determination of kinetics 

assays. According to the 

company, the accessory’s 

sealed environmental 

chambers may be configured 

for temperatures ranging from 150 °C to 900 °C. 

Pike Technologies, Madison, WI; www.piketech.com 

EDXRF head_products spectrometer 

The text_products EDX-LE energy text_products dispersive 

X-ray text_products fluorescence text_products spectrometer 

from text_products Shimadzu text_products 

is designed for 

screening text_products elements company regulated by 

RoHS/EL name address, V directives. website According 

to the company, the spectrometer 

has automated analysis functions 

and a detector that does 

not require liquid nitrogen. Users 

can customize the functions according to the management method. 

According to the company, threshold values can be set for each material 

or element, and the screening judgment can be changed depending 

on the input method used for threshold values. Shimadzu Scientific 

Instruments Inc., Columbia, MD; www.ssi.shimadzu.com 

ICP-OES head_products system 

PerkinElmer’s text_products text_products 

Optima 8x00 

ICP-OES text_products system text_products is designed 

to text_products optimize sample text_products introduction, 

text_products enhance company plasma name 

stability, address, website simplify method 

development, and reduce 

operating costs. The system’s 

sample introduction 

feature is designed to generate 

a constant flow of uniform droplets for stability and detection 

limits. Its plasma generator reportedly uses half the argon of 

traditional systems, and a camera offers continuous viewing of the 

plasma. PerkinElmer, Waltham, MA; www.perkinelmer.com 

Mercury head_products analyzer 

The text_products Model RA-3000F text_products Gold+ 

mercury text_products analyzer text_products from Nippon 

text_products Instruments text_products Corporation 

is text_products designed for company EPA Methods 

1631E name address, and 245.7. website According 

to the company, the instrument 

simplifies low to subppt 

mercury analysis and 

reduces reagent consumption 

and wastes by as much as 

80%. Nippon Instruments 

North America, College Station, TX; www.hg-nic.us 

Raman head_products system for inverted microscopy 

The text_products XploRA INV text_products 

compact analytical Ramam 

chemical text_products imaging text_products 

microscope from HORIBA 

Scientific text_products reportedly text_products combines the automatization 

text_products features company and small footprint name of a 

standard address, confocal websiteRaman microscope with 

the capabilities of an inverted microscope 

for biological applications such as cell 

research, cancer detection, pharmaceutical 

verification of intercellular activities, inclusion 

of microreactors, and incorporation of 

AFM units for tip-enhanced Raman spectroscopy. According to the company, 

the microscope’s open structure permits the use of options and add-ons for 

inverted microscopes, such as micromanipulators, “optical tweezers,” and 

specific enclosures for cell applications. HORIBA Scientific, Edison, NJ; 

www.horiba.com/scientific 

Spectra head_products library 

Fiveash text_products Data Management’s 

text_products 

FDM text_products Raman Organics text_products is 

a text_products library of 500 text_products Raman 

spectra text_products of model company organic 

compounds. name address, According website to the 

company, the spectra in the 

library were run in-focus on a 

6-cm -1 , whitelight-corrected 

spectrometer with a 780- 

nm laser, SNR of 500, and a range of 200–3200 cm -1 . The library 

reportedly is available in most spectral library formats. Fiveash 

Data Management, Madison, WI; www.fdmspectra.com 

Raman head_products analyzer 

The text_products EZRaman-1-9 text_products portable 

Raman text_products analyzer text_products from Enwave 

Optronics text_products is designed text_products to 

minimize text_products fluorescence company and name 

maximize address, website capability of Raman 

analysis in difficult-to-measure 

samples. According to the 

company, the analyzer’s 

excitation wavelength is 

above 900 nm. Enwave 

Optronics, Inc., Irvine, CA; www.enwaveopt.com



Cathodoluminescence microscopes 

Quantitative cathodoluminescence 

microscopes 

from Attolight 

AG are designed for 

analysis from UV to 

IR with 10-nm spatial 

resolution throughout 

the 15–300 K temperature 

range. Two versions are available: the continuous wave 

CL10-Infinity system and the time-resolved CL10-10 system. The 

systems comprise a scanning electron microscope, a nine-axis 

cryo-nanostage, and an integrated cathodoluminescence system. 

Attolight AG, Lausanne, Switzerland; www.attolight.com 

AA spectrophotometer 

Shimadzu’s AA-7000 Series atomic 

absorption spectrophotometer is 

designed for flame and furnace 

analysis using a 3-D optical system. 

According to the company, the 

system achieves flame and furnace 

detection through adjustment of 

the light beam and digital filter 

and includes optical components 

that restrict light loss. The system 

reportedly comes equipped with standard background correction methods, 

a high-speed self-reversal method that provides correction over 

the 185–900 nm range, and safety features, including a vibration sensor 

and multimode automatic gas leak check. Shimadzu Scientific 

Instruments Inc., Columbia, MD; www.ssi.shimadzu.com 

Photovoltaic measurement system 

Newport Corporation’s Oriel 

IQE-200 photovoltaic cell measurement 

system is designed 

for simultaneous measurement 

of the external and internal 

quantum efficiency of solar cells, 

detectors, and other photonto-charge 

converting devices. 

The system reportedly splits the 

beam to allow for concurrent measurements. The system includes a 

light source, a monochromator, and related electronics and software. 

According to the company, the system can be used for the measurement 

of silicon-based cells, amorphous and mono/poly crystalline, 

thin-film cells, copper indium gallium diselenide, and cadmium telluride. 

Newport Corporation, Irvine, CA; www.newport.com 

Microwave digestion system 

Milestone’s UltraWAVE benchtop 

microwave digestion system 

features the company’s 

Single Reaction Chamber 

design. According to the 

company, the system uses 

disposable glass vials instead 

of traditional digestion vessels, 

reducing digestion 

acid volume and lowering 

digestion blanks. 

Milestone, Shelton, CT; 

www.milestonesci.com 

Industrial gas system 

Thermo Fisher’s Antaris industrial 

gas system is designed 

to provide scanning speeds 

as high as 5 Hz at 0.5-cm -1 

resolution. According to the 

company, the FT-IR-based 

analyzer is capable of monitoring 

dozens of gases simultaneously 

while providing 

multicomponent gas analysis. 

Thermo Fisher Scientific, 

Madison, WI; 

www.thermofisher.com 

Electron microscopy software 

The TEAM EDS 2.0 

AnalysisSystem software 

from Edax Inc. 

is designed for use 

with electron microscopes 

and reportedly 

streamlines analysis 

and reporting workflow, 

boosts user productivity, 

reduces analysis 

time, and minimizes error potential. According to the company, the 

software can compare and review multiple maps simultaneously, 

extract spectra from the area of interest using a histogram feature, 

and handle up to 120,000 counts/s. Edax, Inc., Mahwah, NJ; 

www.edax.com 

Crystallographic database 

Release 2011 of the Powder 

Diffraction File from ICDD 

contains 715,953 unique 

material data sets. According 

to the company, each 

data set contains diffraction, 

crystallographic, and 

bibliographic data, as well 

as experimental, instrument, 

and sampling conditions, and 

select physical properties in 

a common standardized format. 

International Centre for Diffraction Data, 

Newtown Square, PA; www.icdd.com 

Dispersive Raman spectrometer 

The RamSpec-HR-1064 

dispersive Raman spectrometer 

from BaySpec is designed 

with a spectral range of 

200–3200 cm -1 , a high-power 

narrowband 1064-nm laser, 

and a high-throughput VPG 

grating-based spectrograph 

with the company’s deepcooled 

InGaAs detector array. 

The spectrometer reportedly 

supports multichannel input ports and features a high-temperature 

extended-length reaction monitoring probes. BaySpec, Inc., 

San Jose, CA; www.bayspec.com


® 

Showcase 

NIPPON INSTRUMENTS 

NORTH AMERICA 

Need a new 

MERCURY ANALYZER? 

Nippon Instruments has 

mercury analyzers for 

most applications. 

® 

MOXTEK 

Contact Us Today! 

Toll-Free: 1.877.247.7241 

Direct: 979.774.3800 

Email: sales@hg-nic.us 

Web: www.hg-nic.us 

New Accessory Catalog! 

Call for Application Notes 

Spectroscopy is planning to publish the next edition 

of The Application Notebook in December 2011. 

As always, the publication will include paid position vendor 

application notes that describe techniques and applications 

of all forms of spectroscopy that are of immediate interest 

to users in industry, academia, and government. 

If your company is interested in participating 

in this special supplement, contact: 

6125 Cottonwood Drive 

Madison, WI 53719 

608.274.2721 

email: sales@piketech.com 


Michael J. Tessalone, Group Publisher • (732) 346-3016 

Edward Fantuzzi, Publisher • (732) 346-3015 

or 

Stephanie Shaffer, East Coast Sales Manager • (508) 481-5885 

Ad Index 

ADVERTISER PG# ADVERTISER PG# ADVERTISER PG# 

Agilent Technologies 3, 5 

Andor Technologies Limited 36, 39 

Applied Rigaku Technologies 22 

B & W Tek Inc. 33, 37 

Bruker Daltonics 49 

Bruker Optics 11 

Craic Technologies 35 

Eastern Analytical Symposium 24 

Edmund Optics 34 

EMCO High Voltage Corp. 13 

Enwave Optronics Inc. 20 

Evans Analytical Group 8 

Fiveash Data Management 25 

Horiba Scientific 

CV4 

International Crystal Lab Outsert 

Materials Research Society 16 

Moxtek, Inc. 23, 58 

New Era Enterprises, Inc. 58 

Newport Corporation 9 

Nippon Instruments North America 58 


15, 42 A–H 

Pike Technologies 30, 31, 58 

Renishaw, Inc. 4 

Retsch, Inc. 18 A–D, 21 

Shimadzu Scientific 

Instruments 

Cover Sticker, 

7, 26 A–D 

Spectron 45 

SPIE 53 

Starna Cells, Inc. 8 

Thermo Fisher Scientific 

CV2 

Winter Conference 2012 

CV3

2012 Winter Conference 

on Plasma Spectrochemistry 

January 9-14, 2012, Tucson, Arizona 

The 2012 Winter Conference explores the most recent applications, 

developments, fundamentals, and research achieved with analytical plasma 

sources including glow discharges, inductively coupled plasmas, laser 

sources, and microwave discharges for elemental trace and ultratrace, stable 

isotope, and elemental speciation analyses. 

More than 300 Invited and Contributed Presentations 

Basic and Advanced Pre-conference Short Courses 

Instrumentation and Plasma Products Exhibition 

Three Special-Topic Workshops 

Twelve Plasma Spectrochemcial Symposia 

Six Heritage Lectures Featuring Distinguished Researchers 

•Advanced Instrumentation and Materials Analysis 

•Agriculture, Food, Nutrition Analysis 

•Aquatic, Earth, Marine Sciences 

•Clinical ICP-MS, Tissue Imaging Analysis 

•Elemental Speciation 

•Environmental Sciences 

•Elemental, Isotopic Forensics 

•Laser Spectrochemistry 

•Nanomaterials Characterization, Analysis 

•Pharmaceutical, Nutraceutical Analysis 

•Sample Introduction, Sample Preparation 

•Semiconductor and High-Purity Materials Analysis 

Hilton Tucson El Conquistador Tennis and Golf Resort 

Pre-Registration Deadline October 14, 2011 

wc2012@chem.umass.edu, http://icpinformation.org 

This is the 17th in a series of biennial meetings featuring developments in 

chemical analysis employing electrical discharge sources know as “plasma 

spectrochemistry”. More than 500 international scientists are expected, and 50 

short courses will be offered.

;SOR5$IHDWXUHVWKHHVWDEOLVKHGSHUIRUPDQFHRI+25,%$6FLHQWL¿FWKHOHDGHULQ 

5DPDQVSHFWURVFRS\DWDVXUSULVLQJSULFH&RPELQLQJPLFURVFRS\DQGFKHPLFDO 

DQDO\VLVWKHV\VWHPUHWDLQVWKHIXOOIXQFWLRQDOLW\RI\RXUPLFURVFRSHFRXSOHGZLWK 

KLJKSHUIRUPDQFH5DPDQVSHFWURVFRS\6HHIRU\RXUVHOI&RQWDFWXVIRUDGHPR 

Now Now with with Inverted inverted 

Microscopes microscopes and and 

Confocal confocal Scanning scanning 

capability 

ZZZKRULEDFRPVFLHQWL¿F 

email: ad.sci@horiba.com

Elevating Excellence in UV-Vis Analyses - Spectroscopy

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?