Automated DPX process - Gerstel

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G L O B A L A N A L Y T I C A L S O L U T I O N S 

News from GERSTEL GmbH & Co. KG · Eberhard-Gerstel-Platz 1 · D-45473 Mülheim an der Ruhr · Germany · Phone +49 (0) 2 08 - 76503-0 · gerstel@gerstel.com 

No. 9 March 2009 

Automated DPX 

Drugs of Abuse: 

Extraction in seconds 

Polymer analysis 

Efficient 

Automated Pyrolysis GC 

Archaeology meets chemistry 

Peeking into 

Pharaoh’s wine glass 

Fats, FAMEs, Fatty Acid Profiles, Rancidity ... 

Focus on 

Food Analysis 

ISSN 1619-0076

In this issue 

News 

■ Cooperation: New 

Solution for Fat 

Determination 3 

Application 

■ Determining 

markers for fatty 

acid decomposition 4 

■ FAMEs: Automated, 

Accurate and Reproducible Fatty Acid 

Derivatization and Determination 8 

Innovation 

■ Polymer analysis: 

Efficient Automated Pyrolysis GC 12 

■ Drugs of abuse: 

Extraction in seconds 14 

■ MAESTRO-Software: 

Perfectly Synchronized 

Sample Prep and Analysis 24 

Interview 

■ Robert J. Collins, Ph.D., President 

GERSTEL, Inc.: Looking 

forward to shaping the future 

of the business 18 

Report 

■ Archaeology meets chemistry: 

Peeking into Pharaoh’s wine glass 21 

GERSTEL online 

You can find more information on products, 

applications and services on the GERSTEL 

home page at www.gerstel.com. 

2 

GERSTEL Solutions Worldwide Editorial 

International Sales under new leadership 

As of July 2008, Ralf Löscher, Ph.D. has joined GERSTEL as 

International Sales Manager. A passionate marathon runner 

with a Ph.D. degree in biology, Dr. Löscher brings new energy 

to the International Sales team, coupled with extensive experience 

in the international analytical instrumentation business. 

Before joining GERSTEL, the frequent flyer was International 

Sales Manager for a reputable supplier of GC and LC Time of 

Flight (TOF) Mass Spectrometry systems and had before that 

worked for a major international corporation, responsible for 

sales of LC and LC/MS instrumentation in Germany. Among 

Ralf Löscher’s many activities in his first year in office have 

been participation in the Analytica China and ArabLab exhibitions, reinvigorating and refocusing 

GERSTEL activities in growth markets with a stronger presence and forming 

new contacts and alliances. 

GERSTEL introduces 

Automated Disposable Pipette 

Extraction (DPX) 

Disposable Pipette Extraction (DPX) is a fast and efficient SPE 

technique used for a wide range of applications such as drugs 

of abuse and therapeutic drug monitoring. Only 200 - 250 µL of 

sample is needed to reach the required limits of detection using a 

fully automated process. The extraction step is performed in 30 - 

60 seconds and the complete process including elution and rinse 

steps takes 3 - 6 minutes depending on the application. Additionally, 

automated DPX is performed during the GC or LC run of the preceding sample ensuring 

maximum throughput and best possible GC/MS or LC/MS system utilization. Elution 

requires only a small amount of solvent, which means that DPX effectively provides 

a concentration step. For many applications, such as pesticides in fruit and vegetables, 

solvent evaporation is not required. For more information on the DPX system, please see 

article on page 14. 

Keeping VOCs and SVOCs out of car interiors 

All leading worldwide car manufacturers and a large number of their suppliers rely on 

GERSTEL technology. Analyses are regularly performed to ensure that materials used in or 

near the vehicle interior do not emit dangerous levels of Volatile and Semi-Volatile Organic 

Compounds (VOCs and SVOCs). A method that is often used world-wide is the VDA Method 

278 from the German Automobile Producers Association (VDA). The VDA 278 method specifies 

thermal desorption/ thermal extraction of materials that are placed directly in thermal 

desorption tubes followed by GC/MS determination. Some manufacturers have their own 

methods based on GERSTEL equipment. Recently, two new methods were established 

by a renowned leading worldwide 

manufacturer. One meth- 

od complements the VDA 278 

method in the determination of 

emissions from materials used 

in car interiors; the other method 

specifies direct air monitoring 

inside the passenger cabins 

of vehicles. As far as GER- 

STEL Solutions Magazine is informed, 

the methods are to be 

used by all world-wide operations 

including suppliers. Both 

methods specify the GERSTEL 

Thermal Desorption System 

(TDS 3) with Thermal Desorption 

Autosampler (TDSA) in combination 

with a GERSTEL Cooled 

Injection System (CIS 4). 

News 

Imprint 

Published by 

GERSTEL GmbH & Co. KG 

Eberhard-Gerstel-Platz 1 

45473 Mülheim an der Ruhr 

Germany 

Editorial Director 

Guido Deußing 

ScienceCommunication 

Neuss, Germany 

guido.deussing@t-online.de 

Translation and editing 

Kaj Petersen 

kaj_petersen@gerstel.de 

Scientific advisory board 

Eike Kleine-Benne, Ph.D. 

eike_kleine-benne@gerstel.de 

Oliver Lerch, Ph.D. 

oliver_lerch@gerstel.de 

Malte Reimold, Ph.D. 

malte_reimold@gerstel.de 

Contact 

gerstel@gerstel.com 

Design 

Paura Design, Hagen, Germany 

www.paura.com 

GERSTEL Solutions Worldwide – March 2009 

ISSN 1619-0076

GERSTEL Solution Worldwide News 

GERSTEL and Büchi in cooperation 

New Solution for Fat Determination 

In order to further improve the patented Caviezel ® rapid analysis method for determination of fat in food 

and feed, the Swiss company Büchi has entered into cooperation with GERSTEL. 

W hen 

it comes to the determination 

of fats in food and feed, the Swiss 

company Büchi plays a substantial 

role. This is due to the patented Caviezel 

method, which is increasingly specified in 

standardized methods. Examples are the 

determination of fat contents that must be 

listed on food products as well as the determination 

of milk fat in foods. 

Following the Caviezel method, an internal 

standard is added to the sample and 

the fat is extracted before undergoing alka- 

Complete solution from Büchi and GERSTEL for the 

determination of fat levels in food and feed products. 

The system is based on the Büchi Extraction unit B 815, 

a 7890 GC from Agilent Technologies with a split/splitless 

inlet and a FID, a GERSTEL MultiPurpose Sampler (MPS) 

and MAESTRO software. 


line digestion. The resulting salts are converted 

to free acids and these are subsequently 

determined using a gas chromatograph 

(GC) with flame ionization detection 

(FID). Leading Büchi managers looked to 

GERSTEL to provide technical and application 

know-how in order to fully unlock the 

potential of the Caviezel method. 

GERSTEL has provided improved automation 

and simplified, accelerated GC 

analysis; in short: a single system that performs 

three different analyses in one short 

run, providing the analyst in the laboratory 

with a simpler, more efficient method. 

Büchi was faced with the challenge of 

improving the automation of their fat analysis 

solution, and they seized the opportunity 

to team up with outside expertise. The 

goal of the GERSTEL-Büchi cooperation 

was to create a comprehensive integrated 

solution, comprised of the Büchi extraction 

unit B 815, an Agilent 7890 GC with a split/ 

splitless inlet and a FID, a GERSTEL MultiPurpose 

Sampler (MPS), integrated software 

control as well as a customized report. 

GERSTEL has exclusive sales and distribution 

rights world-wide for this solution. 

MPS provides high throughput 

Automated sample preparation and sample 

introduction are among the core competencies 

of the GERSTEL MPS, making it 

the ideal candidate for automating all the 

required steps in the GERSTEL-Büchi fat 

analysis solution. „The MPS combines high 

sample capacity with the flexibility to adapt 

to any sample preparation challenge”, says 

Ralf Bremer, Managing Director in charge 

of R&D and Production at GERSTEL. Using 

the PrepAhead functionality of the 

GERSTEL MAESTRO software, the MPS 

can even prepare the next sample or multiple 

samples while the current analysis is 

ongoing. This means that the next sample 

is always prepared and ready for injection 

as soon as the GC finishes running the previous 

sample. The GC system never has to 

be idle; it is always utilized to its fullest capacity 

providing best possible return on in- 

vestment. MAESTRO additionally offers an 

unsurpassed degree of flexibility, which is 

often sorely needed in a production environment. 

Priority samples that need to be 

analyzed as soon as possible, (for example, 

to release a batch of product or to accept 

an incoming raw material shipment), can 

simply be inserted into the running analysis 

sequence table. 

3-in-1 chromatography system 

Büchi’s pre-GERSTEL solution was based 

on a GC method using packed columns, 

an older technology that has limited separation 

power. Because of this limitation, 

three different GC runs, each based on a 

different column was required per sample. 

The total analysis time needed was of course 

quite long and the user had to change and 

condition the columns prior to performing 

the next analysis. Last, but not least, lack of 

separation power resulted in wider peaks 

and less accurate results. “Implementing a 

method that uses capillary column technology 

along with the 7890 GC from Agilent 

Technologies enabled us to improve the 

separation and provide more accurate peak 

integration and thus more accurate results”, 

says Ralf Bremer, “and all three analyses are 

now performed in one run in just 9 minutes”. 

There is no longer a need to change 

columns and this of course improves the 

stability, performance and productivity of 

the system. The system provides values for 

the following: Total fat content, fat profile 

and butter fat (milk fat) content. According 

to Jochen Knecht, Ph.D., Managing Director 

of Büchi Germany and initiator of the 

cooperation, “This is a big step forward”. 

GERSTEL delivers the complete system 

pre-loaded with required analysis method 

parameters and a reporting tool that delivers 

all relevant results nicely organized 

on one page. “To use our system, you don’t 

have to be a GC expert”, says Ralf Bremer, 

“the system produces first class results in 

both production and R&D environments 

– and it does so much faster than it’s predecessor”. 

3

4 

GERSTEL Solutions Worldwide Application 

Determining markers for fatty acid decomposition 

Fighting rancidity 

Assessing the quality of food oils, fats and products that 

contain fatty acids may be cumbersome, but it is necessary 

in order to safeguard product quality and consumer safety. 

Scientists from GERSTEL have developed a new and more 

efficient method for monitoring quality markers in oily matrices: 

Oxidation products such as aldehydes and ketones 

are determined using automated Dynamic Headspace (DHS) 

coupled with GC/MS. 

Text: Guido Deußing 

GERSTEL Solutions Worldwide – March 2009

S almon, 

bluefish, trout, walnuts, rapeseed 

oil, sesame seeds, sunflower 

seeds, soybeans, corn, vegetable oilbased 

spread... this is not a shopping list, 

but these items are recommended as part 

of a healthy and nutritious diet. The reason 

for such a recommendation is that these 

foods contain long-chain polyunsaturated 

fatty acids (LCPs). LCPs can be divided into 

two categories: n-6-fatty acids (formerly 

known as omega-6-fatty acids) among these 

linoleic acid and its derivatives, and n-3-fatty 

acids (formerly known as omega-3-fatty 

acids) to which group the α-linolenic acid 

and its derivatives belong. 

LCPs are said to have many beneficial 

properties. Provided to us via our mother’s 

milk, they provide an essential contribution 

to the development of the brain, nervous 

system and vision in the child. At any 

age, LCPs are known to benefit our heart 

and circulatory system and they prevent or 

reduce arteriosclerosis and related illnesses. 

A deficiency of essential fatty acids can 

have dire negative consequences starting 

with skin conditions, such as calloused skin, 

increased susceptibility for infections, reduced 

growth, hair loss, and reduced blood 

plate-count. 

It is hardly surprising that LCPs are extracted 

from natural products and added 

to foods in order to provide health benefits 

via pre-natal and post-natal baby nutrition. 

These extracts are also used to enrich 

foods that are low in LCPs, such as standard 

bread products, and turn these into 

more valuable so-called functional foods 

that have health benefits. 

Strength and Weakness 

LCPs strengthen us, but are themselves of 

weak constitution. Getting too much “fresh 

air” doesn’t help them either. Oxygen molecules 

attack and destroy their double bonds 

and degradation products are formed. And 

this doesn’t exactly go unnoticed, since compounds 

with unpleasant odors and very low 

odor thresholds are formed. Degradation 

products such as aldehydes and ketones, 

4-heptenal for one, are among the oxidative 

degradation products formed from the fatty 

acids. A concentration of less than 10 ng 

per gram is typically sufficient to give an oil 

or food a distinct rancid smell or flavor. 

For most foods, the contact with oxygen 

cannot be prevented, only reduced, but 

degradation reactions can at least be slowed 

by storing foods at low temperatures. In the 

end, freshness of food oils and fats should 

be monitored. How then to monitor these 

reactions, when odor thresholds are so very 

low? Instrumental techniques are required 

that can extract and concentrate analytes 

without accelerating the very process they 

are meant to monitor, i.e. without heating 



Structure of the determined fatty acid decomposition products 

the sample too much in the process. According 

to Oliver Lerch, Ph.D., application 

scientist at GERSTEL, Static Headspace 

(HS) coupled with GC/MS is a useful 

technique for the determination of volatile 

compounds. However, for the determination 

of oxidation products in oily foods, 

detection limits reached using Headspace 

GC/MS are much too high; it is simply not 

possible to monitor these compounds at the 

required concentration levels using Static 

Headspace. More sensitive techniques are 

needed, such as Headspace Solid Phase Micro-Extraction 

(HS-SPME), which relies on 

a fiber coated with sorbent to concentrate 

analytes from the sample headspace or the 

Dynamic Headspace (DHS) technique, 

which purges and concentrates analytes onto 

an adsorbent trap.“Of these more sensitive 

techniques, we achieved the best results”, 

says Lerch, “when we used the Dynamic 

Headspace (DHS) technique for the 

determination of oxidation markers such as 

aldehydes and ketones”. 

Theory guides, 

experiment decides 

Based on a customer request, Dr. Lerch and 

his colleagues in the Analytical Services Department 

of GERSTEL investigated ten different 

oil samples using automated DHS 

coupled with GC/MS. Most of the samples 

were vegetable oils, among them olive oils 

and rapeseed oils from different producers. 

Two of the samples were fish oils. 

The GERSTEL scientists mainly focused 

on eleven compounds that are known 

degradation products of LCPs: 1-pentene- 

3-one, 2-(E)-pentenal, hexanal, 2-(E)hexenal, 

4-(Z)-heptenal, 2-pentylfurane, 

1-octene-3-one, 2,4-(E,E)-heptadienal, 

2,6-(E,Z)-nonadienal, 2,4-(E,E)-nonadienal 

and 2,4-(E,E)-decadienal. One gram of 

each oil sample was stored in a 20 mL screw 

cap headspace vial. “Weighing in the samples 

was the only manual preparation step 

we had to perform”, says Oliver Lerch, “and 

if we had used the automated weighing option 

for the MPS, even this step could have 

been automated” (cf. GERSTEL Solutions 

Worldwide No. 8). All further sample preparation 

steps, including adding an internal 

standard, performing Dynamic Headspace 

extraction, and introducing the concentrated 

analytes to the GC/MS were performed 

automatically. 

Some details: Standards containing 

from 5 to 500 ng/µL of the target compounds 

were prepared from a 1 µg/µL stock 

solution by dilution with hexane. 1 µL of 

standard solution was added to each of the 

vials containing 1 g of oil sample. The vials 

were placed in the MPS sample trays and 

successively transferred into the DHS station 

agitator, where they were kept at 70 °C 

for 4 minutes for equilibration. DHS extraction 

was then performed for 10 minutes using 

a 50 mL/min flow of nitrogen to purge 

and transfer analytes onto a replaceable Tenax 

TA adsorbent trap for concentration. 

5

Oliver Lerch, Ph.D., The user can specify 

Application Specialist, whether a new trap is 

GERSTEL 

used for each sample 

GmbH & Co. KG 

and of course which 

adsorbent is used, 

the tubes are available 

with any standard 

adsorbent. Following dynamic headspace 

extraction and analyte concentration, 

the adsorbent tube is transferred to 

the GERSTEL Thermal Desorption Unit 

(TDU). Analytes are desorbed in the TDU, 

transferred to the Cooled Injection System 

(CIS), where they are again focused, and finally 

transferred in a narrow band to the 

GC/MS system for identification and quantification. 

Fatty acid decomposition 

provides a clear picture of 

product quality 

Many samples were analyzed using the 

GERSTEL DHS in order to prove its usefulness 

over the entire concentration range 

of decomposition products (generally from 

1 to 100 ng/g) that represents fresh, aged or 

slightly rancid product. 

As an example, Lerch mentions rapeseed 

oil products, which were analyzed as 

described above and categorized: Fresh oils 

mostly had a very low concentration of decomposition 

products. When such oil had 

been stored under normal household conditions 

for six months, however, levels had 

increased significantly (cf. table 1). Apart 

from the aspect of aging, large differences 

in freshly purchased oils from different 

producers were demonstrated (cf. table 2). 

“The statistics supported our findings nicely”, 

says Lerch, “the standard addition calibration 

curves ranged up to 500 ng/g with 

excellent linearity; most correlation coefficients 

were at 0.999”. Standard deviation 

6 


Analyte RT [min] m/z rapseed oil No.1 rapseed oil No.1 

(fresh) in ng/g (aged) in ng/g 

1-Pentene-3-one 7.530 55 1.1 5 

2-(E)-Pentenal 10.432 83 1.5 15.7 

Hexanal 11.892 56 26.1 244.7 

2-(E)-Hexenal 14.532 83 0.4 19.9 

4-(Z)-Heptenal 16.010 94 0.2 4.9 

2-Pentylfurane 18.858 81 0.5 0.3 

1-Octen-3-one 19.304 70 nd 2.3 

2,4-(E,E)-Heptadienal 21.484 81 12 90 

2,6-(E,Z)-Nonadienal 26.900 70 nd nd 

2,4-(E,E)-Nonadienal 29.364 81 0.9 6.9 

2,4-(E,E)-Decadienal 32.964 81 5.9 52.6 

nd = not detected 

Table 1: Comparison of fresh and aged rapeseed oil, which had been stored for 6 months 

under normal household conditions. 

Analyte RT [min] m/z rapseed oil No.1 rapseed oil No.2 

(fresh) in ng/g (fresh) in ng/g 

1-Penten-3-one 7.530 55 1.1 17.5 

2-(E)-Pentenal 10.432 83 1.5 13.0 

Hexanal 11.892 56 26.1 > 500 

2-(E)-Hexenal 14.532 83 0.4 17.9 

4-(Z)-Heptenal 16.010 94 0.2 nd 

2-Pentylfurane 18.858 81 0.5 35.6 

1-Octen-3-one 19.304 70 nd 16.8 

2,4-(E,E)-Heptadienal 21.484 81 12 14.7 

2,6-(E,Z)-Nonadienal 26.900 70 nd 4.3 

2,4-(E,E)-Nonadienal 29.364 81 0.9 63.7 

2,4-(E,E)-Decadienal 32.964 81 5.9 9.2 

nd = not detected 

Table 2: Comparison of two fresh rapeseed oils from different producers. 

The standard addition calibration curves for the different compounds in an oil sample are linear 

up to 500 ng/g. The correlation coefficients were around 0.999 for almost all compounds. 


Analytical conditions 

Adsorbent: Tenax TA 

DHS: Trap temperature: 30 °C; 

Incubation temperature: 70 °C; 

extraction/purge volume: 500 mL N 2 

TDU: Splitless mode; 

Temperature program: 

40 °C (0 min) – 720 °C/min 

to 280 °C (5 min) 

CIS: TDU desorption flow: 70 mL/min 

Analyte transfer: Split 2.5:1 

Temperature program: -150 °C (0 min); 

12 °C/s to 270 °C (7 min). 

Column: DB-624 (Agilent Technologies); Length: 

30 m; I.D. = 0.25 mm; df = 1.4 µm 

Carrier gas: He, constant flow: 1.5 mL/min 

GC oven 40 °C (1 min); 4 °C/min to 170 °C; 

program: 30 °C/min to 240 °C (5 min) 

MSD mode: Selected Ion Monitoring (SIM) 

Repeatability was tested with fresh rapeseed oil which had been spiked with 5 ng/g of 

each analyte. The RSD for five runs was under 6 % for most compounds, this was at 

least as good as the results obtained when performing the analysis with HS-SPME. 



For the determination of quality markers from fatty 

acid decomposition, the GERSTEL scientists relied on 

an automated DHS-GC/MS system. The instrument 

set-up has been implemented successfully for this 

application in customer laboratories. 

and repeatability was tested with fresh rapeseed 

oil that had been spiked with 5 ng/g of 

each target analyte. The RSD for five runs 

was under 6 % for most compounds. The 

method proved to be robust and run-torun 

carry-over was below 0.01% for almost 

all compounds. 

When using the DHS-GC/MS technique, 

the analyst is able to get a clear and 

unequivocal picture of LCP decomposition 

and thereby of the quality and freshness of 

oils, fats, and foods that contain fat. The 

concentration of aldehydes and ketones 

that are “marker compounds” for fat decomposition 

will rise over time as the product 

ages and this makes it easy to determine 

product freshness. The limits of determination 

for the marker compounds are in the 

range from 0.05 to 5 ng/g. The excellent correlation 

is also significant, “it is proof that 

the method is well suited for quality control 

of foods”, says Oliver Lerch. 

7

8 


Automated, Accurate and Reproducible 

Fatty Acid Derivatization and Determination 

Determining FAMEs 

with just-in-time 

sample preparation 

Every laboratory is under pressure to quickly and consistently 

deliver accurate results and to provide clear answers 

faster than ever before while reducing the cost per 

analysis. Analysis systems that meet these criteria are always 

welcome. Application scientists from Bespak Europe 

Ltd. and from Anatune Ltd., both based in the U.K., have 

provided such a solution for automated derivatization 

and GC/MS determination of fatty acids. The approach taken 

to the challenge: Automated sample preparation combined 

with discrimination free introduction of the derivatized 

analytes to the GC/MS system. Automated sample 

preparation in this case includes adding an internal standard 

and derivatizing the fatty acids. 


T 

he more complex the method, the 

higher the demands on the laboratory 

robotics used. A system that is 

able to perform two independent robotic 

functions is by default the more flexible 

and can frequently provide better productivity 

and throughput. The GERSTEL Prep- 

Station happens to be such a system; it was 

successfully used to automate the determination 

of fatty acid profiles and concentrations 

in dried extracts of polymer materials 

used in the pharmaceutical industry. Extraction 

was first performed using accelerated 

solvent extraction (ASE). The work 

was performed in collaboration between 

John Colwell from Bespak Europe Ltd. and 

Ray Perkins, Keith Summerhill and Jonathan 

Angove from Anatune Ltd. in Cambridge, 

U.K., and it was reported in Chromatography 

Today (Vol. 1, Issue 4, Sept./Oct. 

2008, p. 17-19) as well as in Anatune Application 

note AS54 (www.anatune.co.uk). 

Derivatizing fatty acids for 

GC/MS determination 

Animal and vegetable fats are key components 

in our nutrition, but lipids are also 

used in various industrial applications such 

as polymers used for packaging. This means 

that there is a significant analytical market 

for determination of fat content in foods 

and fatty acid profiles in both foods and 

polymers used for packaging. Fats and fat 

oils are mainly triglycerides, glycerol esters 

of monocarboxylic fatty acids (glycerol is 

also known as propane-1,2,3-triol). Most 

triglycerides are made up of three different, 

linear, saturated fatty acids, each with 

an even number of carbon atoms. Triglycerides 

of fatty acids cannot be analyzed directly 

by gas chromatography (GC), they must 

first be hydrolyzed and derivatized. The ester 

bonds are hydrolyzed and the free fatty 

acids that are formed in the process are 

converted to the corresponding fatty acid 

methyl esters (FAMEs). FAMEs are moderately 

apolar and sufficiently volatile to be 

determined by GC or GC/MS. The derivatization 

step is typically quite labor intensive, 

which makes the work by Colwell, Perkins, 

Summerhill and Angove even more interesting. 

Using the PrepStation, the scientists 

implemented and automated a widely used 

manual derivatization method that is based 

on boron trifluoride and methanol (Journal 

of Liquid Research, 1965. 5: p. 600-608). 

Using an established method as a base enabled 

the authors to compare their results 

with those from existing methods. First the 

dried polymer extracts containing fatty acids 

were placed in 10mL vials, and deuterat- 



Analytical conditions 

Injection volume: 1 µL (10 µL syringe) 

Column: Phenomenex Zebron ZB1, 30 m x 240 µm 

(0.1 µm Film) 

Pre-column / Approximately 1 m x 0.53 µm I.D., deactivated 

retention gap: fused silica 

Carrier gas: Helium (1mL/min), constant flow, vacuum 

compensated. 

Oven temperature program: 40 °C (1 min), 10 °C/min to 300 °C (5 min) 

Detection mode: Selected Ion Monitoring (SIM) 

Interface temperature: 280 °C 

MSD setting: Standard Auto Tune (ATUNE) 

MSD Solvent delay: 5 min 

MPS PrepStation as it was used by Colwell, Perkins, Summerhill and Angove 

for derivatization of fatty acids. 

ed fatty acids were added as recovery standards. 

All further steps were performed fully 

automated by the PrepStation. The quantification 

was performed using 1-bromotetradecane 

as internal standard and calibration 

curves were prepared from FAME 

standards. 

Technical Details 

All steps of the derivatization process for 

the fatty acids were performed using the 

GERSTEL PrepStation, which has two independent 

parallel rails, each fitted with independent 

robotic towers capable of performing 

liquid handling steps. 

The upper robot of the GERSTEL Prep- 

Station covers the entire spectrum of liquid 

handling. This includes liquid sample 

introduction, the addition of an internal 

standard, dilution and/or derivatization. 

The lower robot complements the upper 

robot, enabling other types of analyte enrichment 

and sample introduction such as 

Headspace (HS), Solid Phase Micro-Extraction 

(SPME) or automated Solid Phase 

Extraction (SPE). “The MPS PrepStation 

enables efficient automation of complex 

tasks”, says Ray Perkins, owner and General 

Manager of Anatune: “Sample preparation 

is performed during GC or LC analysis 

of the preceding sample, there is no loss 

of productivity, samples are prepared justin-time 

for introduction to the GC or LC 

exactly when it is ready for the next run. 

This means that the analysis system is never 

waiting idly for the next sample. Equally, 

9

Acetone 

Acetone was used as a syringe rinsing solvent 

in the work reported here. Acetone is 

miscible with water and with most organic 

solvents in any ratio. This means that acetone 

is especially well suited for conditioning 

and rinsing solvent syringes to avoid 

sample carry over and surface adhesion 

problems when changing from aqueous 

to oily phases and vice versa. 

Using isotopically 

labelled standards 

In the work reported here, deuterated 

fatty acids were used as recovery standards 

to demonstrate that the derivatization 

process had been completed satisfactorily. 

As an aside, the widely used technique 

of adding deuterated internal standards to 

your sample brings a number of benefits: 

1) The analyst can be almost certain that 

he or she is using internal standards that 

do not occur naturally; there can be little 

doubt that the concentration of the standard 

compound is equal to what was added 

to the sample. 2) The properties of the 

internal standard compounds closely resemble 

the target analytes, which means 

that deviations in response factors, retention 

times and recoveries will be minimal. 

3) The isotopes effectively provide a quality 

check on the analysis: Less check standards 

will need to be run; productivity and 

sample throughput per instrument can be 

increased. 4) In general, using isotopically 

labelled standards can serve as a calibration 

or a calibration check: Less calibration 

standards will need to be run; productivity 

and sample throughput per instrument 

can be increased. 

10 


Table 1 

GC/MS Peak Areas for Methyl Esters from Manually Derivatized Extracts. 

Table 2 

GC/MS Peak Areas for Methyl Esters from Prepstation Derivatized Extracts. 

Table 3 

Comparison of Mean Peak Areas. 

prepared samples are never kept waiting in 

the autosampler. The risk of decomposition 

of labile analytes or labile derivatized analytes 

is thereby greatly reduced, all samples 

are treated exactly the same, which reduces 

the risk of variations in results. 

The PrepStation used in the work reported 

here was equipped with a 1 mL syringe 

and a 10 µL syringe respectively in the 

lower and upper robotic towers. Two heated 

agitators and a Solvent Filling Station 

(SFS) configured with four solvent reservoirs 

were mounted on the system as well. 

One solvent reservoir was filled with HPLCgrade 

water, one with acetone and one with 

internal standard in hexane. The derivatization 

reagent (BF 3 in methanol) was kept 

in a separate 100 mL vial. 

Intelligent scheduling of sample 

preparation and analysis 

The GERSTEL MAESTRO software was 

used to control all sample preparation 

steps. The MAESTRO Scheduler provides 

a complete at-a-glance overview of sample 

preparation and sample introduction 

timing including total sample preparation 

and analysis time for all samples. This functionality 

facilitates planning and scheduling 

of the laboratory work load. The analysis 

was performed on a 6890 GC/5973 MSD 

GC/MS system from Agilent Technologies. 

The PrepStation can be used as a bench top 

WorkStation, independent of the GC/MS 

system or it can be mounted on top of the 

GC/MS system enabling it to perform synchronized, 

overlapping sample preparation 

and sample introduction in one automated 

analysis system. 

Automated derivatization and 

addition of an internal standard 

10 mL sample vials were manually placed 

on the MPS PrepStation. The vials contained 

ASE extracts that had been concentrated 

by solvent evaporation. All further 

steps were fully automated: 1 mL of the BF 3/ 

methanol mixture was aspirated from the 

100 mL storage vial and added to the sample. 

The sample was then transferred to the 

agitator, where it was kept at 70 °C for 5 

minutes under agitation before being returned 

to the sample tray. The 1 mL syringe 

was subsequently used to add 1 mL internal 


Fatty acid methyl esters (FAMEs) 

Fatty acid methyl esters (FAMEs) are 

formed by esterification of fatty acids 

with methanol. The fatty acids are initially 

formed when oils (triglycerides) are 

hydrolyzed. A triglyceride normally contains 

different fatty acids and a mixture 

of different FAMEs is therefore formed in 

the reaction. 

standard (1-Bromotetradecane in hexane) 

to the sample. The deri vatization reaction 

was stopped by adding 3 mL HPLC-grade 

water to the sample. 

Partitioning of FAMEs followed 

by sample introduction 

The FAMEs were partitioned into the organic 

hexane phase, the process was accelerated 

by agitating the vial in the second agitator 

at room temperature for 35 minutes. 

Following an equilibration time of 1 minute 

in the sample tray, the organic phase 

GC/MS Chromatogram (SIM-Mode) of a sample to which deuterated fatty acids have been 

added as recovery standards. Peaks in the order of elution: Methylmyristate (deuterated), 

Methylmyristate, 1-bromotetradecane (internal standard), Methylpalmitate (deuterated), 

Methylpalmitate, Methylstearate (deuterated), Methylstearate. 



that contained the FAMEs had separated 

out and settled. Using the 10 µL syringe, 

the PrepStation aspirated 1 µL of the organic 

phase and introduced it to the GC/ 

MS system. 

High sample throughput and 

accurate results 

„Since the sample preparation steps for this 

analysis require much more time than the 

GC run, the PrepStation gives us significant 

time savings and it greatly improves 

productivity”, says Ray Perkins. The rea- 

Bio diesel 

Did you know? Bio diesel is a vegetable oil 

based fuel that is comparable to diesel fuel 

even though it is not produced from crude 

oil, but rather from vegetable oils, most often 

rapeseed oil, or from animal fats. Bio diesel 

is considered a renewable source of energy; 

chemically it is based on FAMEs. 

son for this can be found in the intelligent 

MAESTRO PrepAhead function that enables 

the user to perform sample preparation 

of one or more samples in parallel 

with ongoing GC/MS analysis. Using the 

PrepAhead function, samples can be prepared 

well ahead of the time when they 

must be ready for injection. This is a winwin 

situation: The chromatography system 

wins in terms of productivity; it never has 

to wait idly for the next sample. The samples 

win in terms of uniform treatment: Every 

sample is introduced immediately after 

it has been prepared; this means that there 

is less risk of sample to sample variations in 

terms of, for example, analyte degradation. 

Of course, the laboratory gains in terms of 

productivity and quality of results. 

The MAESTRO Scheduler even provides 

a complete, at-a-glance overview of 

sample preparation and sample introduction 

timing including total sample preparation 

and analysis time for all samples. 

This functionality facilitates planning and 

scheduling of the laboratory work load. 

Higher recovery and improved 

accuracy through automation 

“This work has shown”, the scientists said, 

“that our proven manual derivatization 

method for methylation of free fatty acids 

can easily and successfully be automated”. 

Furthermore, a comparison between the results 

obtained from manual and automated 

derivatization procedures clearly showed 

the advantages of automation: “The results 

we got from the automated system with the 

MPS PrepStation showed better recovery 

and much lower RSDs for all compounds”, 

Ray Perkins stated, while noting that a part 

of the already low RSDs could even be attributed 

to the Accelerated Solvent Extraction 

(ASE) procedure performed prior to 

the derivatization process. 

11

M 

onomers are generally 

low molecular weight 

compounds with special 

functional groups that enable polymerization. 

Depending on the structure 

and properties of monomers, and 

on the conditions chosen, polymerization 

can lead to the formation 

of linear, branched, or crosslinked 

polymers, which have different 

chemical and physical properties. 

In order to determine the 

structure of a polymer, pyrolysis 

GC is often used as the technique 

of choice; it is a powerful tool in the 

characterization of complex polymers 

whether they are in solid or liquid form 

or in emulsion. 

Curie-Point pyrolyzers are widely used 

for polymer analysis. Some are based on resistive 

heating, some on microwave technology. 

Technical aspects aside, the use of 

special pyrolyzers can be labor intensive, 

sometimes requiring additional cumbersome 

sample preparation steps as well as 

significant added investment volume. A 

different, simpler, and more cost-effective 

way has been described by scientists from 

GERSTEL Solutions Worldwide Innovation 

Polymer analysis 

Efficient Automated Pyrolysis GC 

Scientists from Dow, a leading producer and supplier of chemicals and 

polymer products, have collaborated with GERSTEL scientists in developing 

a novel method for determining the structure and composition 

of polymers. The approach: Following a high-temperature liquid sample 

introduction, pyrolysis is performed in the high-temperature version 

Cooled Injection System 6 (CIS 6) GC inlet. Pyrolysis break-down products 

are subsequently determined using GC/FID or GC/MS. 

DOW and GERSTEL who cooperated on 

developing an attractive alternative to standard 

methods. 

“Instead of a dedicated pyrolyzer, we 

used the CIS 6, the high-temperature version 

of the GERSTEL Cooled Injection 

System (CIS)”, says Patric 

Eckerle, Dow Germany. The 

GERSTEL CIS is the most widely 

used PTV-type inlet in the world. 

Liquid polymers and polymer 

mixtures were pyrolyzed directly 

in the GC inlet in an oxygen-free 

carrier gas atmosphere. Pyrolysis 

break-down products were then 

transferred to the GC column, 

separated and determined using a Flame 

Ionization Detector (FID). 

To prove the validity of the method, the 

scientists analyzed different polymer mixtures: 

1. An emulsion based on a 1:100 styrenebutadiene 

polymer mixture diluted 

with water was examined in order to 

determine recovery rates. In this context, 

Eckerle examined the influence of 

the GERSTEL CryoTrap System (CTS) 

on the quality of the separation. 

Improved peak shape: The GERSTEL CryoTrap System (CTS) significantly improved both 

separation capacity and accuracy in the determination of volatile pyrolysis fragments by 

focusing these and sharpening the peaks. 

12 

2. A styrene-butadiene polymer mixture 

containing varying amounts of emulgated 

copolymer (butylacrylate-styrene) 

was analyzed in order to verify 

the quantitation. 

3. Polyethylene (PE), dissolved in hot xylene, 

was analyzed using two-dimensional 

GC (2D GC and GCxGC). 

For the polymer analysis, the experts 

used a GC system with a GERSTEL Multi- 

Purpose Sampler (MPS), which was used 

for automated sample preparation and sample 

introduction. The MPS was equipped 

with a headspace syringe adapter, a heated 

10 µL syringe and a heated agitator. The GC 

6890 from Agilent Technologies was fitted 

with a GERSTEL CIS 6 programmed temperature 

vaporizer as well as an FID. 

And this is how Eckerle and his colleagues 

approached the task: Following 

sample preparation, 0.5 to 2 µL of the dissolved 

polymer was introduced into the 

cool CIS liner. Solvents were then purged 

from the inlet through the split vent, leaving 

the polymer material condensed on the 

CIS liner walls. The temperature of the CIS 

was kept at 90 °C for 3.5 minutes during the 

First class results: Repeatability of 10 CIS pyrolysis runs of an S/B 

copolymer. The CIS was not cleaned or replaced over the course 

of these runs. 


Success all around: The repeatability experiments gave good results and 

even after ten CIS Pyrolysis runs the liner needed neither replacing nor 

cleaning. “No trace of carry over between samples” said Dirk Bremer, 

GERSTEL R&D Manager, shown to the right in the picture along with 

Patric Eckerle from DOW. 

solvent purge step. It was then programmed 

at 10 °C/min to 600 °C, a temperature sufficiently 

high for complete pyrolysis of the 

sample. The temperature was lowered after 

a one minute hold time. 

The separation was performed using 

GC with and without column switching 

based on the following columns: HP 5 ms, 

30 m x 0.25 mm I.D. x 0.25 µm film thickness 

from Agilent Technologies; in the 2D 

GC (GC x GC) setup, the following column 

was also used: Zebron ZB 50 ms, 30 m x 

0.25 mm ID x 0.25 µm film thickness from 

Phenomenex. The oven temperature was 

kept at 50 °C for 6 minutes and then programmed 

at 15 °C/min to 325 °C (8 min). 

The split flow was 20 mL/min and the FID 

temperature was set to 330 °C (standard 

gas flow conditions). Quantitation was performed 

based on standard addition. 

The purpose of the exercise 

„Using the CIS 6 as a pyrolysis module was 

a complete success“, Patric Eckerle said. „A 

butylacrylate/styrene copolymer in a styrene/butadiene 

copolymer was determined 

qualitatively and quantitatively with minimal 

method development time. In addi- 

Butanol 

Successful quantitation: Peak pattern obtained following 

pyrolysis of a synthetic standard. Standards with various 

concentrations of butylacrylate and styrene in a styrene/ 

butadiene copolymer were pyrolyzed in the project. Results 

were obtained faster than when using spectroscopic 

methods. The key fragments butanol and butylacrylate 

were simultaneously identified by GC/MS. 


Butylacrylate 

Styrene 


Polymer analysis and the instrument set-up used: Agilent Technologies 6890 GC with GERSTEL 

CIS 6 inlet and FID as well as a MultiPurpose Sampler used for automated sample preparation 

and sample introduction. A GERSTEL CryoTrap System (CTS) was used to focus and improve 

the determination of volatile pyrolysis breakdown fragments. 

tion, pyrolysis patterns of standards containing 

different amounts of butylacrylate/styrene 

copolymer in a styrene/butadiene 

copolymer were successfully reproduced. 

Key fragments such as butanol and 

butylacrylate were identified by GC/MS 

and when we added a GERSTEL CryoTrap 

System (CTS), peaks were sharpened significantly, 

enabling us to improve separation 

and to focus and accurately determine 

volatile pyrolysis products”. 

Reproducibility and repeatability were 

excellent, and even after 10 pyrolysis runs, 

it was not necessary to clean or replace the 

CIS liner. “There was no sign of memory 

effects”, said Dirk Bremer, GERSTEL R&D 

Manager. “The CIS 6 - Pyrolysis - GCxGC 

system we used for polymer analysis gave 

a high peak yield and the correlation between 

the peak areas and control standards 

was outstanding”. J. Sep. Sci. 2008, 31, 3416- 

3422. 

The conclusion drawn by Mr. Eckerle is 

that CIS 6 pyrolysis is well suited for several 

things: The determination of monomers 

in polymer mixtures; to gain information 

on micro-structures; and to identify additives 

in polymers. “Our CIS 6 based pyroly- 

sis method is efficient, fast and inexpensive 

- and it requires much less manual sample 

preparation than standard methods”, says 

Eckerle, while adding: “It is also very promising 

that the method is faster than many 

spectroscopy-based methods we have otherwise 

used and the quality of the data is 

outstanding. You could literally place pyrograms 

on top of each other with a perfect 

match and we were able to get both qualitative 

and quantitative results”. 

Pyrolysis GCxGC enables high performance polymer 

analysis: 2D chromatogram of polyethylene fragments 

shown in a 3D presentation. The identification of microstructures, 

information on monomers used, as well as 

the identification of additives, is significantly improved 

compared with standard GC chromatograms. 

Pyrolysis of polyethylene using the GERSTEL CIS 6 inlet. Overlay of two successive pyrolysis 

GC runs. The sample was dissolved in hot toluene. Agitator temperature: 125 °C; Syringe 

temperature: 125 °C. 

13

Forensic Sciences and Toxicology 

Drugs of abuse: Extraction in seconds 

In Forensic Science and in Toxicology, body fluids are regularly analyzed for residues of drugs of abuse, 

therapeutic drugs and of their metabolites. In general this type of analysis requires extensive sample preparation. 

At PittCon 2009, GERSTEL is presenting automated Disposable Pipette Extraction (DPX). DPX is a 

fast and efficient SPE technique used for a wide range of applications such as drugs of abuse, therapeutic 

drug monitoring, comprehensive screening, pharmacology studies (NNK), as well as pesticides in fruit 

and vegetables. DPX is based on unique and patented SPE devices: Pipette tips that incorporate loosely 

contained sorbent material, which is mixed with the sample solution. Turbulent air bubble mixing creates 

a suspension of sorbent in the sample ensuring optimal contact and highly efficient extraction. The 

extraction is performed much faster than with traditional SPE techniques. 

B ody 

fluids represent a complex and 

heterogeneous matrix. Accurate determination 

of drugs, pharmaceuticals 

and metabolites in blood and urine 

requires both a suitable chromatographic 

system and adequate sample preparation. 

Sometimes more than one extraction technique 

is needed for a successful result. Solid 

Phase Extraction (SPE) is among the most 

widely used sample clean-up and analyte 

extraction techniques in forensic and toxicology 

laboratories. 

14 

Automated DPX process 

All steps are performed automatically by the MPS. 

If needed, the sorbent is conditioned with solvent 

prior to the extraction process. 

1 

2 

3 

Sample is drawn into the pipette tip for direct 

contact with the solid phase sorbent. There is 

no contact between the sample and the syringe 

used to aspirate the sample and therefore no 

risk of cross contamination. 

Air is drawn into the pipette tip from below 

through the frit. Turbulent air bubble mixing 

creates a suspension of sorbent in the sample, 

ensuring optimal contact, highly efficient 

extraction, and high recovery. 

The extracted sample is discharged, typically 

after 30 seconds. 

If needed, the sorbent can be washed to remove 

unwanted residue. 


Traditionally, SPE requires the use of 

significant quantities of solvent, some of 

which are toxic. Following several labor intensive 

steps, many methods require that 

the solvent be evaporated in order to concentrate 

the analytes of interest and achieve 

the necessary detection limits. Depending 

on the chemical properties of the analytes, 

a chromatographic determination may also 

require further sample preparation steps 

such as derivatization. The sum total of 

sample preparation steps can amount to a 

4 

significant bottleneck for laboratory productivity 

and a risk to occupational health 

unless adequate and costly safety precautions 

are taken. 

If the tedious and labor intensive steps 

can be eliminated, the overall task can be 

performed more efficiently and faster while 

producing accurate results and using only 

a fraction of the amount of solvent normally 

used. All this is possible thanks to the 

novel Disposable Pipette Extraction (DPX) 

technique developed by Professor William 

Extracted analytes are eluted using a suitable solvent, 

which is added from above for most efficient elution. 

The eluate is collected in a vial for subsequent sample 

introduction to LC/MS or GC/MS. 

The total time required for extraction in the examples 

shown in this article was always less than 6 minutes. 

Sample preparation and GC/MS or LC/MS determination 

can be performed in parallel for best possible throughput 

and system utilization. 


(Bill) E. Brewer, Ph.D. from the University 

of Southern Carolina. Professor Brewer is 

the Owner-President of DPX Labs (www. 

dpxlabs.com). 

The DPX technique has now been automated 

by GERSTEL, a leader in automation 

of sample preparation and sample introduction 

for GC/MS and LC/MS. GERSTEL 

is presenting automated DPX at PittCon 

2009 in Chicago after it was initially introduced 

at the annual meeting of the Society 

of Forensic Toxicologists (SOFT) in Phoenix, 

Arizona (USA) in October 2008. 

„The reactions we got from the forensic 

scientists at the SOFT meeting“, says 

Ro bert J. Collins, Ph.D., President of GER- 

STEL, Inc. in Baltimore, MD, “lead us to believe 

that automated DPX is seen by experts 

as a very promising alternative to standard 

extraction techniques”. 

In order to provide an efficient solution 

for the determination of drugs and metabolites 

in blood in a routine laboratory environment, 

GERSTEL and DPX Labs LLC 

collaborated on automating the DPX technique. 

“DPX immediately struck us as the 

right solution”, says Bob Collins. Furthermore, 

for this application, samples should 

be prepared and derivatized just prior to 

analysis. Just in time sample preparation 

eliminates analyte degradation and underreporting 

of concentration levels since no 

sample is waiting for an extended period of 

time in the autosampler before being analyzed. 

Also, in order to optimize GC/MS 

system utilization and sample throughput, 

a sample should be ready for introduction 

every time the GC/MS finishes its run 

and becomes ready for the next sample. In 

summary, performing GC/MS analysis and 

sample preparation carefully synchronized 

and in parallel benefits both the quality of 

results and the throughput. The MAESTRO 

software with its PrepAhead and Scheduler 

functions makes it extremely easy for the 



Disposable Pipette 

Extraction (DPX) 

In contrast to conventional SPE, DPX does not rely on standard cartridges 

with a packed sorbent bed. DPX is based on unique and patented SPE 

devices: Pipette tips that incorporate loosely contained sorbent material, 

which is mixed with the sample solution. DPX is a dispersive SPE technique, 

turbulent air bubble mixing creates a suspension of sorbent in the 

sample ensuring optimal contact and highly efficient extraction. Extractions 

are performed much faster than with traditional SPE techniques. Elution 

requires only a small amount of solvent, which means that DPX effectively 

provides a concentration step: For many applications, such as pesticides 

in fruit and vegetables, solvent evaporation is not required. 

DPX methods are readily automated using the GERSTEL MPS, which can 

introduce the extract into a GC/MS or LC/MS system. Additional sample preparation 

steps can be performed, including derivatization or adding an internal standard. 

The analyst only needs to place the samples in the 

MPS autosampler and activate the sequence table from 

the MAESTRO software. Everything else is performed 

automatically including GC/MS and LC/MS analysis. 

The patented DPX tips comprise loose solid phase 

sorbent contained inside a pipette tip fitted with a frit at 

the bottom and a polymer barrier at the top. The barrier 

mounted in the upper opening of the DPX tip has some 

additional functions: It is used as a transport adaptor, 

enabling the GERSTEL MPS to move the tip around 

and fully automate the DPX process. An orifice in the 

transport adapter enables the autosampler syringe to 

deposit liquids and to aspirate air through the sample/sorbent 

suspension for highly efficient mixing and 

extraction. „DPX is a unique and patented extraction 

technique that provides the user a previously unheard 

Ralf Bremer, 

GERSTEL Managing 

Director for R&D 

and production 

of level of automation, efficiency and throughput“, says Ralf Bremer, Managing 

Director for R&D and production. GERSTEL has exclusive rights to sell automated 

DPX instrumentation world-wide. 

The DPX process is wonderfully simple: DPX tips are placed on the sample 

tray of the MPS. Aspirating the sample; adding liquids for conditioning, rinsing 

or elution; and aspirating air through the sample/sorbent suspension for efficient 

mixing – all this is performed by the microliter syringe in the autosampler. Depending 

on the application, the sorbent is conditioned using a suitable solvent: This is 

aspirated into the DPX tip out of a vial or added from above. The defined amount 

of sample is aspirated into the DPX tip without making contact with the syringe 

or syringe needle. “There is no cross-contamination between samples”, says Ralf 

Bremer and notes: “Furthermore, since DPX is a dispersive SPE technique, it is 

not affected by flow rates or by changes in the flow path (i.e. channelling) through 

the sorbent. Such things have no impact on the extraction efficiency.“ 

When the DPX tip is safely retracted from the sample vial, air is aspirated 

through it, through the polymer frit and through the sample inside. “Fine air bubbles 

quickly rise through the sample / sorbent suspension resulting in extremely 

efficient, turbulent mixing. This significantly accelerates the extraction of analytes 

onto the sorbent”, says Bremer. The extraction is performed under optimal 

conditions while requiring much less sorbent material than other SPE techniques. 

The extracted sample is now discarded into a waste vial. A rinse step follows and 

the extracted analytes are then eluted into an empty vial using a suitable solvent. 

The DPX tip is discarded and the MPS is ready for the next sample. 

When performing SPE extractions manually, it is often necessary to concentrate 

the extract by evaporating the solvent under an inert atmosphere and then 

adding a keeper solvent to take up the residue. Such a labor intensive and time 

consuming step is not required when performing fully automated DPX: “The extract 

is simply introduced into the GC/MS system using a Large Volume Injection 

(LVI). The solvent is evaporated in the GC inlet and the analytes are concentrated 

inside the inlet liner, provided you have a temperature programmable GC inlet 

such as the GERSTEL Cooled Injection System (CIS)”, says Ralf Bremer. 

15

analyst to plan, optimize, and set up the 

whole process. 

From theory to practice 

In order to test the MPS-DPX-CIS- 

GC/MS system in practice, the scientists 

analyzed blood and urine samples 

that had been spiked with different drugs 

and pharmaceuticals. Compounds determined 

included amphetamines, benzodiazepines, 

cocaine and methadone as well 

as tetrahydrocannabinol (THC) and metabolites. 

For details, please see the graphic 

representations on this page. The analysis 

was performed using deuterated internal 

standards: For blood samples, d5-PCP 

(0.2 ppm) was used. For the determination 

of benzodiazepines, d5-Nordiazepam (0.2 

ppm) and d5-OH-Alprazolam (0.2 ppm) 

were used. For the opiates, equivalent deuterated 

compounds were used (each at a 

level of 0.1 ppm). 

16 

TIC 


EIC 

Drug Average RSD 

Amphetamine 13.9 % 

Methamphetamine 14.4 % 

Meperidine 5.8 % 

PCP 2.2 % 

Methadone 3.3 % 

Methaqualone 3.6 % 

Amitriptyline 3.1 % 

Cocaine 3.8 % 

Cis Doxepin 2.8 % 

Imipramine 3.3 % 

Trans Doxepin 3.2 % 

Pentazocine 5.3 % 

Codeine 4.2 % 

Desipramine 6.4 % 

Required manual sample 

preparation steps 

Preparing blood samples: 0.5 mL of acetonitrile 

was added to a 0.25 mL sample of 

whole blood followed by mixing to precipitate 

proteins in the sample. The mixture 

was centrifuged and the supernatant transferred 

to a clean labelled test tube containing 

0.1 mL of 0.1 M HCl. 

Preparing urine samples for the determination 

of benzodiazepines: In order to 

determine the total level of free, bound and 

metabolized residues of drugs and pharmaceuticals 

in urine, hydrolysis must be performed 

of the respective conjugates, such 

as for example glucuronides of benzodiazepines, 

which are metabolites of the drugs 

that are formed to facilitate excretion of the 

substances from the body. 

The hydrolysis reaction is started by 

add ing 10 µL of a solution of the enzyme 

b-glucuronidase and 50 µL of a 0.1 M sodi- 

Drugs of abuse in blood: Total ion chromatogram of a DPX extract 

of 250 µL whole blood spiked at 0.5 ppm with drugs of abuse using 

d5-PCP as internal standard. Chromatograms from the 5th and 

20th injections are shown alongside each other to demonstrate 

the ruggedness of the analysis. The insert shows the extracted 

ion chromatogram (EIC) from the 5th injection. The sample was 

protein precipitated with 0.5 mL acetonitrile, and the supernatant 

was transferred to clean tubes. After adding 0.1 mL of 0.1 M HCl, 

automated DPX was performed. 1) Meperidine, 2) d5-PCP (ion 

205), 3) PCP, 4) Methadone, 5) Methaqualone, 6) Amitriptyline, 7) 

Cocaine, 8) cis-Doxepin, 9) Imipramine, 10) trans-Doxepin, 11) 

Desipramine, 12) Pentazocine, 13) Codeine (Septum bleed from 

vial cap after repeat injections from the same vial). 

um phosphate buffer with pH 4 to a 0.2 mL 

sample of urine. The mixture is kept at 55 °C 

for two hours and is then allowed to cool to 

room temperature. Acetonitrile (0.25 mL) 

is then added in order to preci pitate the 

enzyme. Following centrifugation, the supernatant 

is transferred to a clean, labelled 

test tube and 200 µL of 0.1M HCl is added. 

The prepared samples are then placed in the 

MPS sample tray. 

Automated Disposable Pipette Extraction 

(DPX) is subsequently performed on 

the prepared samples using the MultiPurpose 

Sampler (MPS) equipped with 1 mL 

CX tips from DPX Labs (www.dpxlabs. 

com). As the name suggests, CX tips contain 

a novel and unique cation exchange material 

with additional slightly apolar characteristics. 

The DPX process is completely 

automated: 250 µL of a 30 % solution 

of acetonitrile in water is dispensed onto 

the DPX sorbent inside the tip for condi- 

Analysis conditions 

CIS: 1 min solvent purge (150 mL/ 

min); splitless; temperature 

program: 80 °C (1 min) – 

12 °C/min – 300 °C (3 min) 

Column: 30 m HP5 (Agilent Technologies); 

di = 0.25 mm; df = 0.25 µm 

Pneumatics: He, constant flow, 1.5 mL/min 

GC oven: 100 °C (0.5 min) – 20 °C/min 

– 300 °C (12.5 min) 

MSD: Selectable Full Scan 

or SIM mode 


THC and metabolites in blood: Total ion chromatogram of 10 ng/mL THC and 

metabolites extracted from 0.5 mL whole blood following protein precipitation, 

centrifugation and DPX-RP. Derivatization was performed in the CIS inlet by 

injecting 50 µL of DPX eluent together with 20 µL of 50/50 BSTFA/acetonitrile. 

No additional solvent evaporation or derivatization step was performed. Analytes: 

1) THC-TMS, 2) OH-THC-TMS, 3) COOH-THC-2TMS 

tioning. The conditioning solvent is subsequently 

discarded to waste. The DPX tip is 

then immersed into the sample and a defined 

volume is aspirated into the tip. Air is 

then aspirated into the tip, causing turbulent 

mixing and efficient extraction of analytes 

into the sorbent. Following a 30 second 

equilibration time, in which the sorbent 

is allowed to settle, the extracted sample is 

discarded to waste. The sorbent is rinsed 

twice, first with 0.5 mL of a 30 % solution of 

Acetonitrile in water and then with 0.5 mL 

acetonitrile. The extracted analytes are eluted 

using 0.7 mL of a solution consisting of 

2 % concentrated ammonia, 78 % CH 2Cl 2 

and 20 % isopropanol. 

The eluate was dispensed directly into 

an autosampler vial. The total amount of 

time required for extraction and liquid handling 

was less than 6 minutes per sample. 

Instrumentation 

The analysis was performed on a 6890N/5975 

(inert XL) GC/MS system from Agilent 

Technologies. The GC was fitted with a 

Cooled Injection System (CIS 4) PTV-type 

inlet. An MPS PrepStation with DPX option 

and MAESTRO Software control was used 

for automated sample preparation and sample 

introduction. The complete system including 

GC/MS was operated using one integrated 

method and one sequence table directly 

from the Agilent Technologies Chem- 

Station Software, operated integrated with 

the MAESTRO software. 

Derivatization 

Some analytes must be derivatized to enable 

GC/MS determination. „The Cooled Injection 

System (CIS) inlet offers an inert and 

temperature programmable environment“, 

says Prof. Brewer, „which is highly suited 



to evaporating and purging excess solvent 

while simultaneously, or at least sequentially, 

performing derivatization of analytes.“ 

For the derivatization of benzodiazepines, 

20 µL of 50 % N-(t-butyldimethylsilyl)-N-methyl-trifluoracetamide 

(MTB- 

STFA) in acetonitrile was aspirated into the 

autosampler syringe followed by 20 µL of air 

and 50 µL of the DPX eluate. „The resulting 

„Sandwich“ injection was performed slowly, 

using a programmed stop flow method 

to ensure that the solvent was completely 

removed through the split vent prior to the 

derivatization step”, the application specialist 

explains. The CIS temperature quickly 

ramped to 300 °C, which started the derivatization 

process and helped transfer the derivatized 

analytes to the GC column in splitless 

mode for highest possible recovery and 

lowest limits of determination. 

“Automated analyte derivatization in 

the GC inlet proved to be both simple and 

highly practical”, said Prof. Brewer. “The 

method was successfully applied to the determination 

of benzodiazepines in blood. 

Compounds that were not successfully derivatized 

in this way were derivatized directly 

in the sample vial”. For this approach, the 

DPX eluate was evaporated to dryness under 

a flow of nitrogen in the sample vial. 50 

µL of MTBSTFA and 50 µL of ethyl acetate 

were added and the mixture kept at 70 °C 

for 20 minutes. When the extract had cooled 

off, 50 µL of the solution was introduced to 

the CIS inlet using the Large Volume Injection 

(LVI) technique. 

The conclusion 

reached by the experts 

“As we had expected, the analysis based on 

automated DPX delivers excellent results”, 

said Bob Collins. Even though all analyses 

Benzodiazepines in urine: Total ion chromatogram of 0.2 ppm benzodiazepines in 

0.2 mL urine following enzymatic hydrolysis and DPX. Derivatization was performed in 

the CIS inlet by injecting 50 µL of DPX eluent together with 20 µL of 50/50 MTBSTFA/ 

acetonitrile. No separate solvent evaporation step was performed. Increasing the 

sample volume to 0.5 mL and performing multiple DPX extractions would increase 

the sensitivity. 1) Diazepam, 2) Nordiazepam-d5-TBDMS, 3) Nordiazepam-TBDMS, 

4) Flunitrazepam, 5) 7-aminoflunitrazepam, 6) Oxazepam-2TBDMS, 7) Temazepam-TBDMS, 

8) Nitrazepam, 9) Lorazepam-2TBDMS, 10) Clonazepam-TBDMS, 

11) Alprazolam, 12) a-OH-Alprazolam-d5-TBDMS, 13) a-OH-Alprazolam-TBDMS 

were performed on very small sample volumes 

(250 µL blood or 200 µL urine), the 

resulting peak intensities were highly satisfactory 

– even in full scan mode. The MultiPurpose 

Sampler (MPS) with automated 

DPX enables fast sample preparation of difficult 

samples while delivering high sensitivity 

and accurate results. The additional 

liquid handling capabilities of the dual rail 

MPS PrepStation enabled full automation 

of all the required liquid handling steps such 

as derivatization and addition of an internal 

standard. This added level of automation 

provided best possible productivity and 

throughput. The instrument combination 

used proved to be especially useful for the 

determination of basic drugs such as cocaine, 

methadone, PCP, TCAs and Meperidine. 

Most benzodiazepines were easy to determine 

using MTBSTFA derivatization 

in the GC inlet. The following were determined: 

Diazepam, Nordiazepam, Oxazepam, 

Temazepam, Alprazolam and a-OHalprazolam. 

“DPX combined with GC/MS 

determination provided excellent results 

for the 11 listed benzodiazepines in urine“, 

Bob Collins notes, ”plus we got good recovery 

and great sensitivity for the opiates. For 

most opiates, we achieved limits of determination 

under 1 ng/mL in whole blood”. 

Ralf Bremer, General Manager for production 

and R&D, is thrilled about the use of the 

CIS 4, PTV-type inlet for evaporative concentration 

and analyte derivatization: “This 

year, we are celebrating the 25th anniversary 

of the introduction of the first GERSTEL 

CIS. It is very reassuring to see that the constant 

improvements we have engineered into 

the CIS over the years enable us to stay 

well ahead of the competition”. 

17

GSW: You have been with GERSTEL Inc. for 

15 years, you are so to speak a man of the 

first hour, and you have been in 

charge of steering the company 

for a number of years. Please 

describe to us how the company 

has developed? 

Bob Collins: In the beginning it 

was a very small operation of 

just two people. The challenge 

was covering the entire country 

instantly. This had to be done 

even though we were so small, 

since U.S. companies typically 

have a country-wide presence 

and need to replicate their solutions 

in other branches as well. 

So you can’t just sell in Baltimore, you also 

need to be able to support customers in Los 

Angeles, which is a 6-7 hour flight away. In the 

beginning, I was the sales person, the service 

engineer and the technical support person all 

in one. With such a small staff it was a real 

challenge initially, but as sales grew, we added 

people and things became easier. We have had 

organic, steady growth, adding people as sales 

grew while doing our best to provide worldclass 

support along with the world-class products 

and solutions GERSTEL offers. 

What is the distinguishing feature of GERSTEL, 

Inc.? What are the strengths of your company 

and what is the added value you offer your 

customers? 

The unique feature of GERSTEL is of course 

the products themselves; they do things that 

no other products can. They provide unequalled 

sample preparation capabilities 

that are easy to use due to our advanced 

software. They allow the analyst to achieve 

very low detection limits in even the most 

difficult sample matrices; within the field 

of chemical analysis our products and so- 

GERSTEL Solutions Worldwide Interview 

Interview with Robert J. Collins, GERSTEL Inc., USA 

Looking forward to shaping 

the future of the business 

GERSTEL is recognized as one of the leading providers of automated sample preparation and sample introduction 

solutions for GC/MS and increasingly for LC/MS. After building a reputation as a leader in specialized 

solutions for GC in Germany and Western Europe, management decided to expand GERSTEL’s presence 

to the United States. In 1994, the company took the plunge and GERSTEL, Inc. was founded. Today, 

almost 15 years later, GERSTEL, Inc. has moved into new larger headquarters near the Baltimore Washington 

International Airport in order to provide the best possible support for its large and growing family of 

customers. GERSTEL Solutions worldwide spoke with long-time GERSTEL, Inc. President Robert (Bob) Collins, 

Ph.D., about how GERSTEL, Inc. developed over the past 15 years. 

18 

GERSTEL, Inc. 

President Robert J. 

Collins, Ph.D. 

lutions are truly unique. Additionally, we 

offer comprehensive application support, 

technical training and service 

support. Our customers consistently 

tell us that we do this 

better than anyone else, in the 

US alone, we have five application 

scientists. Our service engineers 

are excellent, and our 

sales people are very experienced 

and knowledgeable. This 

can be a great help to customers 

when they are trying to determine 

which GERSTEL product 

best suits their needs. All system 

purchases from GERSTEL in the 

U.S. include a training course. 

We have just moved to new headquarters 

with a wonderful new training facility that 

has greatly improved our capacity. Also, every 

time you call GERSTEL, you get an actual 

person on the line. You can speak directly 

to an application scientist or a service engineer; 

you are not just asked to leave a message 

or just given a reference number with 

the message that you will be called back. We 

try to give personalized high-level support 

in all aspects of the business. 

In order to be innovative and to offer customers 

added value, a company needs to invest in 

research and development. What is GERSTEL 

doing in that field? 

We are doing a lot! GERSTEL, Inc. is a subsidiary, 

product development is performed 

in Germany, but we are very active in method 

development and provide ideas for product 

development based on input from our U.S. 

customers and our sales and support staff. 

This combined with input from Japan and 

Germany allows GERSTEL to constantly refine 

existing products and develop new ones. 

If you look at GERSTEL products and solu- 

tions today, you can see we’ve come a long 

way from just GC inlets. We now offer a wide 

range of sample preparation and analyte enrichment 

capabilities that can be used in almost 

all areas of GC and LC analysis. 

Speaking of innovations, you are a long time 

PittCon exhibitor, which products are you highlighting 

this year? 

The main thing we will be highlighting is the 

new automated DPX technology, which we 

are extremely excited about. DPX is an abbreviation 

of Disposable Pipette Extraction, 

it is essentially a miniaturized, fast SPE technique. 

We are also showing a host of other 

new solutions: Automated SPE; Automated 

SPME Fiber Exchange, a multi-fiber system 

that will be a useful tool especially for the 

food, flavor and beverage industry. It enables 

the use of different SPME phases in one automated 

sequence for flexible and efficient 

screening and analysis. 

Will any other innovations from the past year 

be shown? 

A lot of automated sample preparation techniques 

have been developed over the past 

few years that we will present such as an 

automated blood analyzer with centrifugation, 

sonication, sample heating and barcode 

reading. We have also integrated sample 

weighing. We have a great tool kit for automated 

sample preparation. 

Better than the competition? 

I would say yes, since it is much more modular, 

easier to customize to the exact needs 

of each laboratory and surprisingly inexpensive 

compared with other robotic solutions. 

And since everything is controlled through 

our powerful, yet easy to use, MAESTRO 

software, it is really amazing how quickly 

we can put a solution together. 


Why do you think that DPX will be a success? 

DPX is really a faster, more efficient form 

of the SPE technique. And it is much less 

sensitive to changes in method parameters 

such as flow rates, with which you have to 

be really careful when you do SPE. DPX is 

just so much quicker than SPE and that will 

be a key factor. 

You introduced automated DPX at the Society of 

Forensic Toxicology (SOFT) 2008 annual meeting 

in the U.S. – what was the reaction? 

DPX was extremely well received; we had 

a great deal of interest from people visiting 

our booth, and our presentations. Since 

then, DPX Labs has developed even more 

phase materials and we have been working 

closely with them to provide automated solutions 

for the entire range of tips available. 

We have already sold some systems in the 

U.S. and are about to place a system into 

one of the largest drug testing laboratories 

in the United States. 

Is DPX useful outside the field of Forensic Science? 

Oh yes, DPX is useful for anything where you 

need sample clean-up, extraction and concentration. 

Areas that come to mind immediately 

are clinical analysis, foods, including 

the QuEChERS method, and beverages. 


Impressions of the new company building 


Looking back: Which were the most successful 

products from GERSTEL over the years? 

Where do the particular strengths of the company 

lie? 

A big success has been what we call „bundled 

systems“, for example the Thermal Desorption 

Unit (TDU) bundle, which is extremely 

flexible. I’ve always said that a typical day 

has the analyst come to work in the morning; 

and while having his or her first cup of 

coffee and thinking of what the plans are for 

the day, the first emergency comes through 

the door. The original plan is set aside, and 

the emergency must be dealt with. The TDU 

bundle enables the analyst to quickly set up 

and use any of eight different analytical techniques 

and allows them to quickly meet any 

challenge. I would have loved to have had 

one when I was active in the laboratory. 

The U.S. is a geographically very large country. 

How do you support customers throughout 

such a vast territory? What is your strategy 

for reaching every part of the map both in 

terms of sales and support? 

We use a hybrid system with GERSTEL employed 

regional sales managers that work 

with independent manufacturers’ representatives 

to cover their territory. We have 

four regional managers and about 35 manufacturers’ 

representatives covering the U.S. 

and Canada. Every region has direct service 

support as well as third party service engineers 

that support our customers throughout 

this huge nation. 

Is it important for U.S. customers that GERSTEL 

products are made in Germany? 

I don’t think U.S. customers place a lot of 

emphasis on where a product comes from, 

as long as the quality is good. Of course, German 

engineering and German products, especially 

cars, have a great reputation, but every 

company has to build its own reputation, 

and more importantly, maintain this reputation 

by delivering quality products and service. 

If you look at our products, they definitely 

live up to the expectations associated 

with “Made in Germany”. 

GERSTEL develops, produces and markets advanced 

instruments and technologies. These 

are used in many different industries, universities, 

state and public laboratories, and on top 

of it all, they are used both for routine analysis 

and for research. How do you go about supporting 

so many different types of users and keeping 

them satisfied? 

Before we sell a system we make sure that it 

fits the customer’s needs, and allows them 

to successfully do whatever they need to do. 

This eliminates a lot of problems up front. 

19

We do not try to put product out there just to 

rack up big sales numbers, this doesn’t help 

the customer or us. Secondly, as I mentioned 

before, all system purchases from GERSTEL 

in the U.S. include a training course at our 

Baltimore facilities. This covers theory, 

hands-on instrument operation and maintenance. 

This ensures that the user is fully 

trained to perform the analysis. Additionally, 

an extensive set of maintenance videos 

and user manuals help a lot. Thirdly, our 

users can always reach us over the phone 

or through e-mail. Most problems are little 

things that are quickly resolved. Fast assistance 

means that productivity is quickly 

restored. This saves a lot of everyone’s time 

and makes the customer very happy. Large 

companies simply cannot or just do not offer 

that level of support. 

How well is GERSTEL accepted in the market 

place? 

Our recognition and acceptance has grown 

enormously over the past 10 years. In the 

food, flavor and fragrance markets, for example, 

almost everyone has our products. 

20 


In State Health labs across the nation and 

in some homeland security applications we 

are also well accepted. In a U.S.-wide project 

headed up by the Centers for Disease Control, 

we equipped almost every State Public 

Health laboratory in the U.S. with a unified 

custom solution that included sample preparation, 

sample introduction and integrated 

custom software for homeland security. 

There are about 100 of these units out there 

now. Apart from that, we have steadily built 

a presence in the U.S. and now have a loyal 

following. Word of mouth also helps us 

grow – and we still have tremendous room 

to grow, which is a good thing. 

What was your reason to move to new and larger 

headquarters? 

As we grew at our previous location, we added 

more and more space as adjacent suites 

became available. The disadvantage of this 

approach is that the layout of the facility is 

always inefficient because you have to use 

the previous tenant’s design and it can only 

be changed by expensive and disruptive demolition. 

In the end, the laboratory, train- 

ing, and warehouse facilities were no longer 

adequate for the size of the business, 

and before our lease was about to expire, 

I decided to look into options to alleviate 

the problems we were having. We were 

very fortunate to find an excellent property 

close to the Baltimore airport. We were 

able to design the interior from scratch and 

it has greatly improved our work-flow. We 

can now do a lot of things simultaneously, 

which gives us more flexibility and better 

efficiency. In the end we are now able to 

provide even better support for our growing 

number of customers. 

Do the new headquarters mean that you’ll 

pursue a different corporate strategy? Which 

plans and goals do you have and what is the 

outlook? 

A big part of our plans with the new facility 

is that we want to increase the amount 

of customer training and bring more customers 

in to see our instrumentation first 

hand. We also recently had an Agilent 6410 

Triple Quad LC/MS/MS system installed in 

our applications laboratory in order to support 

our expansion into the LC/MS market. 

We now have the facilities and the people we 

need to take the business to the next level – 

I am very much looking forward to shaping 

the future of the business ... 

... and GERSTEL is the leader in automated 

sample preparation? 

Yes, I think we are; especially if you are 

talking about combined automated sample 

preparation and sample introduction. 

When you combine our technologies and 

hardware with MAESTRO software control 

and extensive applications support, it 

is fair to say that GERSTEL is a recognized 

leader. 

Is it important in this context that GERSTEL is 

a family owned company? 

I think it is extremely important. When we 

make a decision to pursue an opportunity, 

we can take a much longer view than publicly 

listed companies and that has made 

a huge difference. Customer support and 

satisfaction is the overriding priority at 

GERSTEL, and as a family owned company, 

we can stick to this priority without pressure 

from share holders that are looking for 

short term gains. Our customers know and 

see this and it makes a big difference for employees 

too; they are more involved, better 

informed and feel more secure. 

When other companies are laying off employees, 

do you see this as an opportunity? 

Yes, absolutely, and not just because it 

makes it easier for us to compete. It is a 

great opportunity to get excellent and experienced 

new people on board to help GER- 

STEL continue the steady growth that we 

have seen for over ten years now. 


Archaeology meets chemistry 

W ine 

from ancient Egypt is thought 

to have been honey-sweet – though 

now it is just bone-dry. What was 

once refreshing, stimulating and thirstquenching 

has mostly evaporated; only dust 

and residues remain in the 3-5 millennia old 

amphorae that were found in the tombs of 

those ancient rulers and demigods, the Pharaohs. 

On their way to the netherworld, they 

were given gold and ample riches along with 

food and amphorae filled with precious 

wine. One amphora was marked: “Year 5. 

Wine of the House of Tutankhamen, Ruler 

of-the Southern On, the Western River. By 

the chief Vintner Khaa.’’ (Source BBC). 

Some tombs are embellished with wall 

paintings depicting scenes from ancient 

Egyptian vineyards (cf. picture on p. 22). 

From such graphical renderings, as well as 

from a separate hieroglyph for the word 

“wine”, archaeologists were able to deter- 

GERSTEL Solutions Worldwide Report 

* 

Peeking into Pharaoh’s glass 

* Ancient Egyptian sign for „Wine“ 

Details on viticulture in ancient Egypt are quite well understood by 

modern-day archaeologists. But what exactly was in Pharaoh’s glass 

when he savored the gift of the wine gods – and was it just imbibed for 

relaxation and merriment or was it taken as a stimulating aphrodisiac 

or maybe prescribed by his physician to cure or alleviate pharaohnic 

ailments? Answers to these questions have eluded us for ages. When 

archaeologists recently consulted analytical chemists armed with 

thermal desorption GC/MS systems, information began to trickle out, 

offering insight into ingredients used in ancient Egyptian wine. 


mine that grapes were being grown and wine 

produced as early as 3,000 B.C. in the Nile 

Delta (Lower Egypt). At that point a thriving 

wine-producing industry controlled by 

the rulers had already taken root. Vines were 

planted in pits filled with fertile Nile river 

silt. Given sufficient irrigation, vines could 

be grown successfully in oases. 

Sacrifices to the gods 

Archaeologists have found evidence that 

wine was well appreciated for festive occasions 

in ancient Egypt. The only drop of bitterness 

in the chalice was that many an outstanding 

droplet was reserved for the gods 

and donated as sacrifice. We have until now 

relied only on speculation as to what Tutankhamen 

and his contemporaries imbibed 

when “communicating” with the wine gods. 

The uncovered amphorae have been completely 

dry and empty; the wine evaporat- 

Polyphenols are universally praised 

for their positive health effects, in large 

part ascribed to antioxidant and radical 

scavenging properties. One might 

also turn to grapes, raisins, black currants, 

cranberries or elderberries for a 

less stimulating source. Most chemical 

research on polyphenols is reportedly 

performed on wine. 

ed an eternity ago. Not until chemists were 

called upon to inspect the grave goods more 

closely did hard facts begin to emerge. In 

the amphorae found in the grave of Tutankhamen, 

malvidine-3-glucoside was identified 

among the remains (Armen Mirzoian 

et al., „Analytical Chemistry“, Vol. 76, No. 6, 

March 15, 2004). 

This compound is one of the more stable 

anthocyanins, the group of compounds that 

lends a warm red hue to the class of wines 

known as red wines. The 18 year old Pharaoh, 

in other words, had been given amphorae 

of red wine to accompany him, possibly 

wine that he had favored during his short 

life. As an aside, anthocyanins form the main 

group of flavonoids that, along with phenols, 

make up the class polyphenols, which are 

thought to have positive health effects. 

Equally scientifically intriguing was the 

search for wine residues in 700 wine jugs 

found in Abydos, Egypt. The jugs had been 

dated to 3,150 B.C., around 1,800 years prior 

to the birth of Tutankhamen. They were 

found in what was probably the tomb of the 

first Egyptian Pharaoh, Scorpion, from the 

first dynasty. Initial research had revealed 

that the Abydos jugs had contained around 

4,000 Liters (1,000 Gallons) of wine from 

the Valley of Jordan, about 600 km (400 

miles) away. 

The project described here was performed 

by scientists from the Museum of 

the University of Pennsylvania (MASCA) in 

Philadelphia, PA, and from the Beverage Alcohol 

Laboratory in Beltsville, MD, part of 

the U.S. Alcohol and Tobacco, Tax and Trade 

To look into the soul of a wine that no longer has a body, 

the scientists had no other option but to grind clay from 

the inside of the amphorae and jugs and extract winerelated 

substances from the granulate. 

21


Mural in the tomb of Nebamun, soldier in the army of Pharaoh Thutmose IV (Photo: archive). 

SPME Total Ion Chromatogram (top) of the Abydos sample and enlarged (12.00-13.60 min) Selected Ion 

Chromatograms (Middle), shown along with mass spectra and library mass spectra of select compounds (below). 

22 

Bureau (TTB). The scope of the project was 

to determine volatile and semi-volatile compounds 

in the wine residues, but not necessarily 

to determine the origins of the wine. 

In order to have a historically differentiated 

reference, a wine amphora from the Nubian 

town of Djebel Adda, dating back to the 

year 400 A.D., was analyzed as well. 

Wine tasting based 

on pottery shards 

To look into the soul of a wine that no longer 

has a body, the scientists had no choice 

but to grind the ancient pottery and extract 

the oenological residues from the resulting 

powder using acidic or alkaline solutions. 

The extracts were filtered and analyzed using 

chromatographic techniques. The following 

provides an overview of the methods 

used for analysis. 

Traces of resin and herbs 

The results: In both samples, the scientists 

identified a range of terpenoids, esters and 

alcohols as well as various volatile compounds 

and L-tartaric acid. This was definitive 

proof that the amphorae and jugs had 

contained wine. Further, the identified compounds 

indicated that resin and herbs had 

been added to the wines, making them a kind 

of ancient day Retsina wine, possibly similar 

to what is produced, and mainly served 

to tourists, in Greece today. 

The project provided facts that support 

the theory of a preference for wines 

enriched with resin and herbs at the court 

of the Pharaohs, covering the entire period 

from the beginning of the ancient Egyptian 

High Culture (Abydos find) until the latter 

parts (Djebel Adda find). The herbs may 

have been added mainly to produce a sought 

after taste or they could have been added 

for medicinal purposes. Herbs and tree res- 

Section of „Papyrus Ebers“ (1,500 B.C.) a 20 meter long list 

of medicinal recipes, and thereby the most comprehensive 

documentation of medical knowledge in ancient Egypt 

known to man. The content mainly deals with internal 

diseases and their treatment. The papyrus was acquired for 

the University of Leipzig, Germany in 1872 by Georg Ebers 

(1837-1898), Professor of Egyptology. 


Solid Phase Micro-Extraction (SPME) 

A 50/30 µm DVB/CAR/PDMS fiber was 

used. The fiber was immersed in a sodium 

chloride solution containing the sample 

powder inside the sample vial for 40 

min. at a temperature of 80 °C. The concentrated 

analytes were desorbed from 

the SPME fiber in the GC inlet for 3 minutes 

at 250°C. The SPME process was 

automated using the GERSTEL Multi- 

Purpose Sampler (MPS). 

Gas Chromatography / Mass 

Spectrometry (GC/MS) 

A GC/MS system consisting of a 6890 

GC and a 5973 MSD, both from Agilent 

Technologies, was used. Separation was 

achieved using a HP 5MS column, 30 

m x 0.25 mm ID x 0.25 µm film thickness. 

Analyte transfer was performed in 

splitless mode, the MSD was set to scan 

mode from m/z = 40 to m/z = 400. GC 

oven program was started at 60 °C and 

programmed to 240°C at 3 °C/min. Carrier: 

Helium at 1.2 ml/min constant flow. 

Compounds were identified using mass 

spectral libraries and Kovats Retention 

Indices, calculated from a series of n-alkanes 

from C 5 to C 22. 

Thermal Desorption 

Residues from amphorae and jugs were 

also desorbed, or thermally extracted, 

using a Thermal Desorption System 

(TDS) from GERSTEL. The desorption 

temperature was programmed from a 

50 °C starting temperature to 250 °C at 

a rate of 50 °C/min. 

Liquid Chromatography – Tandem Mass 

Spectrometry (LC/MS/MS) 

A Waters Acquity UPLC and a Micro- 

Mass Quattro Premier XE Triple Quadropole 

mass spectrometer were used. LC 

parameters: UPLC BEH C18 column. 

Isocratic flow at 0.20 mL/min, 98 % 

H 2O : 2 % ACN, 0.1 % Formic acid. MS/ 

MS: Electron Spray Ionization (ESI), Cap. 

4.50 KV, CV 20 V, CE 16 V. 

in were part of the ancient Egyptian pharmacopoeia 

as we have learned from 13 ancient 

papyri with information on medicine 

and various recipes. Among these are the 

“Papyrus Smith” (2,500 B.C.), the “Papyrus 

Ebers” (1,500 B.C.) or the “Papyrus Hearst” 

(1,500 B.C.), all named after the people by 

whom they were later purchased. In “Papyrus 

Smith”, diseases were clearly divided into 

incurable and curable afflictions; for the latter 

group, systematic instructions for treatment 

were listed. Knowledge about anatomy 

and physiology (e.g. functions of organs) 

was, however, very limited, which means that 

physicians at the time were quickly out of 

options for effective treatment. In many 

cases patients were diagnosed as being possessed 

by demons; prayers or redemptive 

magic was prescribed. Empirical work, religion 

and authorized magic often went hand 



Multiple reaction monitoring (MRM) LC/MS/MS 

chromatogram traces of an L-tartaric acid standard 

(top) based on the m/z 149 and 87 molecular 

fragments. The middle and bottom traces are from 

the aqueous extracts of the samples from Abydos 

and Djebel Adda respectively. 

RT (min) Compound Abydos Djebel Adda Possible origin 

3.75 1-Hexanol x Wine 

5.81 Benzaldehyde x x Wine 

5.62 Camphene x Pine 

5.99 Heptanol x Wine 

6.27 Phenol x Mint 

6.48 Menthene x Mint 

7.68 p-Cymol x x Pine, Rosemary 

7.82 Limonene x Mint, Pine 

7.97 Benzyl alcohol x Wine 

9.27 1-Octanol x Mint, Wine 

9.96 Fenchone x Rosemary, Fennel, Sage 

10.09 2-Nonanone x 

10.91 Phenethyl alcohol x Wine 

10.92 Fenchol x x Pine 

12.17 Camphene x x Pine, Mint, Wild Fennel, Sage, Mugwort, Rosemary 

12.53 g-Heptalactone x 

13.05 Borneol x x Pine, Rosemary, Mint, Oregano 

13.31 1-Nonanol x Mint 

13.42 L-Menthol x Mint 

14.12 a-Terpineol x Pine, Mint, Wine 

14.46 Ethyloctanoate x Wine 

15.63 Cuminaldehyde x Rosemary 

16.41 Carvone x Mint, Yarrow, Wild Fennel, Sage, Mugwort 

17.57 Ethyl Salicylate x Wine 

17.67 Decanol x Mint 

18.55 Thymol x Mint, Wild Fennel, Sage, Basil, Thyme 

23.11 Ethyl Decanoate x Wine 

23.13 Vanillin x Rosemary, Thyme 

25.53 Geranyl Acetone x Rosemary 

35.34 Farnesol x Pine 

37.76 Benzyl Benzoate x Pine 

38.85 Ethyl Palmitate x x Wine 

45.76 Ethyl Stearate x x Wine 

46.28 Manoyl Oxide x Pine 

47.65 Biformene x Pine 

56.24 Methyl Dehydroabietate x Pine 

Compounds in the jugs from Abydos and amphorae from Djebel Adda identified using SPME-GC/MS 

and Thermal Desorption GC/MS. 

in hand. 

A word on alcohol content of the wine in 

ancient Egypt: Alcohol plays a useful role as 

an extraction solvent for, and carrier of, active 

compounds in herbal medicine. The intoxicating 

role is of course equally well recognized 

and this seems to have been a cherished 

side-effect to what the doctor ordered. 

Beer, not wine, was the national beverage in 

ancient Egypt, often used in religious ceremonies 

and as a meal-time beverage. Legend 

has it that Osiris, the god of the underworld, 

taught humans how to brew beer. Prepared 

Selected Ion Chromatogram of the peak at 23.13 

min; retention time and mass spectrum match 

those of vanillin. 

from malted barley, a type of wheat called 

emmer and date juice, beer was counted as a 

staple food on the same level as bread. Brewing 

beer was of course also a way of preserving 

drinking water and keeping it from being 

infested with undesirable microorganisms. 

Those ancient Egyptians who could afford 

it often preferred to drink wine when they 

wanted to have a good old time. Almost four 

thousand years ago, an Egyptian teacher lamented 

that one of his students was leading 

a debauched and alcoholized life. “Oh if only 

you would recognize that wine is a horror, if 

only you would forget the chalice”. 

23

GERSTEL GmbH & Co. KG 

Eberhard-Gerstel-Platz 1 

45473 Mülheim an der Ruhr 

Germany 

+49 208 - 7 65 03-0 

+49 208 - 7 65 03 33 

gerstel@gerstel.com 

www.gerstel.com 


G L O B A L A N A L Y T I C A L S O L U T I O N S 

GERSTEL, Inc. 

701 Caton Digital Research Drive Center 

Suite 1510 Caton J Center Drive, 

Linthicum, Suite H MD 21090 

USA Baltimore, MD 21227 

USA 

+1 410 - 247 5885 

+1 410 - 247 5887 

sales@gerstelus.com 

info@gerstelus.com 

www.gerstelus.com 

GERSTEL MAESTRO Software 

Perfectly Synchronized 

Sample Preparation and Analysis 

Perfect synchronization is essential, when performing sample preparation and chromatographic analysis in 

parallel for optimized productivity. Automated sample preparation requires reliable and compatible hardware 

combined with integrated software control of the whole analysis process, including LC/MS or GC/MS analysis. 

The GERSTEL MAESTRO software helps analysts find the fastest route to the results. The complete process 

can be viewed using the graphical Scheduler to aid laboratory workflow planning and allows the analyst to 

monitor important details while viewing the whole picture. 

MAESTRO supports a range of 

automated sample preparation 

techniques for LC/MS and GC/MS: 

• Liquid handling (e.g., adding an 

internal standard, derivatizing, 

extracting or generating a series 

of calibration standards) 

• Centrifugation, Sonication, 

Weighing and Bar Code Reading 

• Disposable Pipette EXtraction 

(DPX) 

• Solid Phase Extraction (SPE) 

• Dynamic Headspace (DHS) 

• Thermal Desorption (TD) and 

Thermal Extraction from µ-vials 

• Twister/Stir Bar Sorptive 

Extraction (SBSE) 

• Headspace and Solid Phase 

Micro-Extraction (SPME) 

Sample preparation for GC/MS or LC/MS 

analysis can involve sample clean-up and 

liquid handling processes, such as additions 

or dilutions, as well as analyte concentration 

steps to reach the required limits of detection 

(LOD, see box). 

Using the MAESTRO Software, sample 

preparation is performed while chromatography 

of the preceding sample is in progress 

to optimize throughput. 

Urgent samples can be 

inserted into the running 

sequence without slowing 

or halting the workflow. If the analysis 

has been stopped before completion 

of the entire batch, an e-mail 

notification can be sent to one 

or more addresses enabling users 

to quickly restore productivity. 

Context-sensitive help is 

available for all functions and 

entry fields in the software and 

a remote support software tool is 

included. The user can enable the 

GERSTEL support team to view the software 

screen via internet for fast and efficient 

advice on trouble-shooting 

or for 

training as needed. 

GERSTEL AG 

Enterprise 

Surentalstrasse 10 

6210 Sursee 

Switzerland 

Subject to change. GERSTEL ® , GRAPHPACK ® and TWISTER ® Subject to change. GERSTEL are registered trademarks of GERSTEL GmbH & Co. KG. 

Printed in Germany · 0309 · © Copyright by GERSTEL GmbH & Co. KG 

® , GRAPHPACK ® and TWISTER ® are registered trademarks of GERSTEL GmbH & Co. KG. 

Printed in Germany · 0208b · © Copyright by GERSTEL GmbH & Co. KG 

+41 41 - 9 21 97 23 

+41 41 - 9 21 97 25 

gerstel@ch.gerstel.com 

www.gerstel.de 

MAESTRO operates independently, or 

fully integrated with the Agilent ChemStation 

software, or coupled with the Agilent 

MassHunter software. Only one method and 

one sequence table is required to operate the 

complete system from sample prep to GC/ 

MS or LC/MS analysis. Further information: 

www.gerstel.com/maestro_eng.htm 

GERSTEL K.K. 

2-13-18 Nakane, Meguro-ku 

152-0031 Tokyo 

Dai-Hyaku Seimei Toritsudai 

Ekimae Bldg 2F 

Japan 

+81 3 57 31 53 21 

+81 3 57 31 53 22 

info@gerstel.co.jp 

www.gerstel.co.jp

Automated DPX process - Gerstel

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