2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
P59 DETECTION OF FOREIGN ORGANIC
SubSTANCES IN wATER AND bIOLOGICAL
SAMPLES
e. SAVELIEVA, n. KORYAGInA, n. KHLEBnIKOVA,
n. GOnCHAROV and A. RADILOV
Research Institute of Hygiene, Occupational Pathology and
Human Ecology, Saint-Petersburg, Russia,
esavelieva59@mail.ru
Introduction
The chemical analysis of biomedical samples (bodily
fluids, tissues) aimed at revealing exposure to toxic chemicals
(TCs) can be directed to the following targets:
(i) TCs themselves, when their metabolism is slow
enough,
(ii) Low-molecular metabolites of TCs,
(iii) High-molecular adducts of TCs with proteins.
Right choice of target (marker) with account for the life
cycle of a TC (adsorption–distribution – metabolism – excretion)
predetermines success of analysis. The targets (i) and
(ii) are more convenient to determine by conventional GC-
MS methods but are unsuitable for retrospective analysis in
view of their short life time in the organism. We developed
procedures for the determination in biomedical samples of all
the three groups of biomarkers of TCs.
Results and Discussion
Direct analysis of a TC in biomedical samples was considered
to be a rational approach in toxicokinetic research
on fluoroacetic acid, one of the most potent metabolic poinsons
(FAA). Salts of FAA are still used in some countries for
rodent population control; deadly poisoning of humans and
farm animals was also described. At our laboratory, procedures
for the determination of O-alkyl esters of methylphosphonic
acid (low-molecular metabolites of organophosphorus
warfare agents, OPWAs) and thiodiglycol (metabolite of
sulfur mustard) were also developed. These metabolites are
products of both biogenic and abiogenic hydrolysis of the
parent agents, and, therefore, their determination in environmental
samples is actual for retrospective analysis aimed at
establishing the fact and degree of environmental pollution
with the corresponding agents. Of particular importance for
forensic analysis are universal procedures suitable both for
water and for biological fluids. We developed universal procedures
for the determination of FAA, methylphosphonic acid
(MPA), ethyl MPA (marker of VX), isopropyl MPA (marker
of sarin), isobutyl MPA (marker of Russian VX), pinacolyl
MPA (soman marker), and thiodiglycol in water, urine, and
blood plasma.
For retrospective establishment of exposure to TCs,
procedures for the determination of reactivation products
of blood plasma butyryl cholinesterase (BChE) inhibited by
OPWAs and of thiodiglycol isolated by alkaline hydrolysis
from albumin adducts. These procedures all are based on GC/
MS combined with solid-phase microextraction (SPME).
s450
Solid-phase microextraction is a unique method that
allows one to combine on a single stage extraction from a
matrix, concentration, and injection of a sample. SPME offers
a great advantage of analyzing the whole sample rather
than its aliquot, and, therefore, is more than about an order
of magnitude more sensitive compared with traditional separation
and concentration methods. SPME poses no threat of
contamination of a GCMS system by matrix components. Of
key importance for successful SPME analysis is right choice
of microfiber, conditions for sorption (temperature, time,
sample mixing mode, ionic strength of analyzed solution)
and desorption (temperature, delay time).
Therefore, in developing an SPME procedure, one
should optimize the following parameters:
•
•
•
•
Type of microfiber
Sorption and thermodesorption temperatures of target
analytes
Sorption and thermodesorption times
Ionic strength of the solution.
Before GC/MS analysis nonvolatile target compounds
were derivatized either in situ with subsequent concentration
of the volatile derivative on microfiber (analysis for FAA)
or directly on microfiber with vapors of derivatizing agents
(analysis for MPA and its O-alkyl esters).
In what follows we schematically represent certain of
the mentioned procedures. Fig. 1. shows the block scheme of
the determination of sodium fluoroacetate in various media.
In view of the fact that the volatile derivative, ethyl fluoroacetate,
is sampled from equilibrium vapor, the sample matrix
scarcely affects the results of analysis. The developed procedure
is universal and can be applied both for control of drinking
water and for toxicokinetic and forensic investigations.
Fig. 1. Block scheme of the unified procedure for the determination
of sodium fluoroacetate in water and biomedical samples
by SPME-GCMS
The detection limits are 0.001 mg ml –1 for drinking
and natural waters, 0.01 mg ml –1 for blood plasma, and
0.01 mg ml –1 for organ homogenates (without recounting for
dry weigh). The procedure is described in detail in ref. 1 .
For the determination of the low-molecular metabolites
of organophosphorus warfare agents, MPA and its alkyl