Nerve agents analytical methods

Among the above-mentioned methods, SPME is relatively new. It combines sample preparation and injection of the sample into one step. Analytes are adsorbed on a polymeric fiber coated with a stationary phase such as polydimethylsiloxane, which is thermally desorbed in the injection port at 250 °C. The successful use of the technique for the GC/MS analysis of the nerve agents in water has been described (42). Levels of less than... 

This paper will review the known metabolic pathways of CW agents, excretion profiles where these have been measured, and methods for the analysis of metabolites in urine or blood. Examples are provided of detection in cases of human exposure. The review focuses mainly on sulfur mustard and nerve agents that represent the greatest global CW threat, and for which most analytical methods have been developed. 

Analytical Methods for Nerve Agents and Their Metabolites... 

A number of modifications/improvements to methods for the analysis of metabolites of sulfur and nitrogen mustards, and hydrolysis products of nerve agents, have been reported in a special issue of the Journal of Analytical Toxicology, 28 (5) (2004) pp. 305-392. 

Early CWA detectors were quite primitive and included primarily chemical-reactive dyes in paints. These were insensitive and therefore unreliable (Smart, 1997). Later technology used more sensitive chemical dyes in other formats such as paper tickets. Modem detectors now consist of fieldable IR spectrometers and an alarm system designed to warn of the presence of CWAs on the battlefield or in an enclosed space. Several rehable tests for the diagnosis of CWA exposure have been developed. To detect HD exposure, the level of thiodiglycol, a metabolite of HD, is quantitated in the urine using a gas chromatography/mass spectrometry (GC/MS) analytical method (Jakubowski et al., 1990 TB MED 296, 1996). Nerve agent exposure is detected in the field by the use of a fieldable Ellman assay to determine chohnesterase inhibition in the blood (Ellman et al., 1961 TB MED 296, 1996). 

TABLE 19,1 Analytical Methods for Assay of Nerve Agent Hydrolysis Products References... 

TABLE 19,3 Analytical Methods Using Nerve Agent Adducts to Biomolecules References... 

There are clear ethical constraints that prevent human research that could definitively answer the questions of concern regarding the military operational and civilian health risks of exposure to low-levels of chemical warfare nerve agents. Only three sources of relevant human data are available for analysis. These data are from either past human volunteer studies, reports based on accidental exposures, or reports of the consequences of malicious releases of the agents. While these sources are valuable, the data have some limitations for deriving dose-response relationships because of inferior analytical and clinical methods or the lack of precise estimates of exposure. 

Hill and Martin (2002) presented a review of conventional analytical methods for CWAs. They discussed various. sensors, such as surface acoustic wave sensors, electrochemical sen.sors, spectrophotometric sensors, immunochemical sen.sors, and IMS detector. For OP nerve agents. FPD and MS are the detectors of choice when coupled with GC or LC. Miniature ion trap ma.ss spectrometer has been described for the detection of nerve agents in the field (Patterson et at., 2002 Riter et al., 2002). A book published by the Institute of Medicine and the National Research Council explains the use of various types of detectors for nerve agents as well as CWAs (lOM, 1999). 

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