Agilent ICP-MS Journal - Agilent Technologies

User Profile: ExperTox
Inc. Specialists in
Toxicology Testing
Ernie Lykissa,
ExperTox Inc, Texas, USA.
Introduction
ExperTox Inc. was established in
1996 by Environmental Engineer
Loretta M. Anderson and Forensic
Toxicologist Dr. Ernest Lykissa, to
address the increasing demand for
toxicology studies from industry
and State police departments.
They equipped the laboratory with
state-of-the-art instrumentation to
tackle a varied workload including
requests from individuals, industry
or the police for certified analysis
of biological specimens to include
hair, urine blood, tissue and saliva.
The most common request is to test
for any evidence of poisoning or
exposure to certain organics or heavy
metals. ExperTox also conduct a full
range of employment testing, including
drug testing for non-prescribed
narcotics. They will also establish
baseline levels of residual metals
present in contractors and employees
working in heavy industry who may
be exposed to toxic substances in the
course of their work. Other examples
of work undertaken include:
• Analysis of food and nutritional
supplements
• Analysis of date rape drugs,
drugs of abuse and steroids
• Expert witness testimony in
family, civil and criminal courts
A team of chemists, biologists,
medical technicians and toxicologists
use a full range of analytical
equipment, including ICP-MS, GC-
MS, LC-MS, EIA (electrothermal
atomization), HPLC and microscopic
analysis, to carry out a full evaluation
and report for each project.
The Role of ICP-MS
ExperTox Inc were one of the first
laboratories in the US to endorse
the Agilent ICP-MS. They purchased
a 4500 in 1996 and one of the first
7500 systems in 2000. With previous
experience as the head of a drug
testing department for a large
pharmaceutical company, Dr Lykissa
was confident that all the heavy metal
determinations could be handled
directly by ICP-MS without the need
to invest in additional techniques
like Graphite Furnace Atomic
Absorption (GFAAS). "GFAAS is old
technology, ICP-MS is a much more
powerful and productive technique
that suits our needs perfectly,"
commented Dr Lykissa.
Analysis of Clinical Samples
Primarily, ICP-MS is used to
determine heavy metals such as lead,
cadmium, chromium, cobalt, mercury
and platinum. First, all samples of
urine, blood, and other tissues are
hydrolyzed in 5 % HNO3. Gold is
added (10 ug/L) to stabilize any
mercury present in the specimens.
The toxic concentration of most
heavy metals is in the high ppb (ug/L)
range. Anything higher than that is
indicative of an acute exposure and
would require further investigation.
The samples are then analyzed using
the 7500a ICP-MS fitted with a High
Solids (Babington type) nebulizer
and standard quartz spray chamber.
The instrument is optimized using
a solution containing Li, Y, Ce and
Tl (10ppb) for standard low-oxide/low
interference levels (~0.3% CeO/Ce)
while maintaining high sensitivity
across the mass range. Typical
instrumental conditions are displayed
in Table 1.
Parameter Value
Forward Power 1200 W
Plasma Gas Flow 15.0 L min-1
Auxiliary Gas Flow 1.0 L min-1
Nebulizer Gas Flow 1.2 L min-1
Sampling Depth 0.5 mm
Integration time 3 sec
No. replicates per 3
analysis
Table 1 Instrumental conditions
Results and Discussion
For quantitative results, the
instrument is calibrated using a
mixed concentration multielement
solution containing Ag, As, Cd, Co,
Cr, Ni, Pb, Se, Al, Cu. Hg is calibrated
with its own standard. Analysts
also employ commercial quality
controls for whole blood and urine
that contain the above metals in
normal and elevated concentrations.
Table 1 shows 7500a data obtained
on five different days compared to
reference values obtained from preassayed
blood reference standards.
Element Ref ICP-MS data
value
ng/mL
over 5 days
As 88 88.2, 83.5, 85.3, 88.9,
88.2
Cd 13 12.4, 12.8, 12.5, 12.8,
12.8
Cr 60 54.6, 58.5, 59,2, 55.6,
56.7
Pb 57 57.2, 57.0, 57.7, 56.8,
57,2
Hg 43 42.4,42.8,44.2,43.5,
43.6
Se 570 562 , 573, 576, 568,
567
Table 1. ICP-MS control performance data over
5 different days
Case Study Example
ExperTox worked on the case of a
prominent cardiologist who suspected
an estranged girlfriend of poisoning
him. Tests determined the arsenic
level in his urine to be 850 ug/L -
way in excess of normal levels of
20 ug/L and toxic levels of 100
ug/L. Could this be a case of foul
play? Upon close examination and
testing of his house, CCA (copper,
chromium, arsenic salt) treated
wood and insulation material were
discovered in the attic. Recent
flooding in the area had created
damp conditions for mold to thrive.
The mold had absorbed considerable
amounts of the toxic CCA which was
spread throughout the house after
gaining access to the air-conditioning
ducts. The physician abandoned his
house immediately and his urinary
arsenic levels returned to normal,
in a period of 30 days! Case solved.
For more information on Expertox
visit: http://www.expertox.com
7500 Makes TV Debut!
A 7500 ICP-MS and other Agilent equipment,
including a 5973 GC-MS, can be seen in the
current series of the US TV show Crime Scene
Investigation (CSI). CSI is a very popular
American primetime series that features a
team of forensic investigators trained to solve
crimes by careful analysis of the crime scene
evidence. Equipping the forensics lab with
state-of-the-art instrumentation adds to the
credibility of the show - if not to its popularity.
4 Agilent ICP-MS Journal January 2004 - Issue 18 www.agilent.com/chem/icpms