Examination of Firearms Review: 2007 to 2010 - Interpol

3.3.4 Chemical warfare agents
Organophosphorus nerve agents and sulphur or nitrogen mustard are among
the most toxic organic compounds used as chemical warfare agents by both
military and terrorists. An overview of biological markers of exposure to
chemical warfare agents was reported; metabolites, protein, and/or DNA
adducts were identified for most nerve agents and vesicants, and validated in
experimental animals or in a small number of human exposures [345].
An analytical method for determining the metabolic hydrolysis products of
organophosphorus nerve agents, such as sarin (GB) and cyclosarin (GF), has
been developed using LC-ESI-TOFMS, with an LOD of 2 ng/mL in plasma
[346], and HILIC-MS/MS down to LOQ of 1 ng/mL in human urine [347]. The
biomarker ethyl methylphosphonofluoridate (VX-G) of VX was measured in red
blood cells (RBC) following treatment with fluoride ion using isotope-dilution
GC-MS/MS, with an absolute detection limit of < 1 pg on column [348]. The
method was used for analysis of minipig RBC samples following exposure to
VX vapor [349,350], and concluded that VX-G was a more precise indicator for
severity of exposure than analysis of acetylcholinesterase (AChE) inhibition
[349].
Four methods were used to monitor the reaction of albumin with soman:
Progressive inhibition of the aryl acylamidase activity of albumin, the release of
fluoride ion from soman, 31 P NMR, and MS. The study concluded that
soman-albumin adducts detected by MS was useful for the diagnosis of soman
exposure [351]. A fluoride ion-based regeneration assay with isotope dilution,
followed by large volume injection GC-CI-MS, was developed for the detection
of soman in rat plasma. With the use of an isotope labeled internal standard,
the LOD was 5.65 pg (on column) with an average recovery of 93% [352].
Nanoparticle-based electrochemical immunosensor provides an opportunity to
develop field-deployable, sensitive, and quantitative biosensors for monitoring
exposure to a variety of OP pesticides and nerve agents, by the detection of
the potential marker phosphorylated acetylcholinesterase (Phospho-AChE).
Experimental results showed that the developed electrochemical quartz crystal
microbalance technique can allow the detection of Phospho-AChE in human
plasma, with a detection limit of 0.020 nM-8.0 pM [353,354]. The AChE
enzyme activity was investigated using a carbon nanotube-based
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