Analysis of Nerve Agent Degradation Products

Formation of alkyl phosphonic acid degradation products in the environment follows a highly specific hydrolysis pathway from the parent dialkyl phosphonate ester CWA s. Nerve agent hydrolysis products are unique compared with 

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S.A. Oehrle and P.C. Bossle, Analysis of nerve agent degradation products using capillary ion electrophoresis, J. Chromatogr A, 692, 247-252 (1995). 

Lagarrigue, M., et al. (2009) Analysis of nerve agent degradation products in high-conductivity matrices by tran-... 

Table 3.1 Analysis of nerve agent degradation products using capillary electrophoresis. Reprinted from Journal of Chromatography A, 1217, 45, Copyright 2010, with permission from Elsevier... 

Xgg were achieved with an analysis time of 30 min [9]. More recently, Kolakowski et al. 128] demonstrated the use of atmospheric pressure ionization-high field asymmetric waveform ion mobility mass spectrometry for the analysis of nerve agent degradation products in food samples. 

LC/MS ANALYSIS OF NERVE AGENTS, THEIR DEGRADATION PRODUCTS, AND IMPURITIES... 

Combined Analysis of Nerve Agents and their Degradation Products... 

VIII. TRACE ANALYSIS OF NERVE AGENTS AND THEIR DEGRADATION PRODUCTS IN VERIFICATION... 

Elashvili. I. (2Enzymatic analysis of nerve agents and their degradation products. Paper pte.scntcd at the 24th Army Science Conference Tran.sformattonal Science and Technology for Current and Future Force, KP-13. Available at www,a.sc2004.com/ 23rd/summaries/k/kp-13.pdf. 

Capillary electrophoresis (CE) is a separation technique for ionic or ionizable compounds. CE is particularly attractive because the instrumentation is inexpensive and separations are quick and efficient. As with GC and LC, CE can be coupled to and flame photometric detection (FED) to detect alkylphosphonic acids [30-32]. Indirect UV absorbance detection with CE has also been used for the analysis of nerve agents and their degradation products [33]. In an attempt to meet the demands of portable and efficient field instruments, miniaturized analytical systems with CE microchips have also been made for the separation and detection of alkylphosphonic nerve agents [34]. The aforementioned CE procedures all provide rapid identification without extensive sample preparation. CE is most likely to be used as a guide in order to select the appropriate methods for further analysis by more definitive techniques such as GC-MS, as most of the products detected and analysed are degradation products [35]. A review depicting various CE separation techniques, lab-on-a-chip technology and detection limits has been compiled by Pumera and is shown in Table 3.1. 

Alkyl phosphonic acid nerve agent degradation products present difficulties for sample preparation and ultra-trace analysis due to their high polarity, low volatility and lack of a good chromophore for ultraviolet (UV) detection. 

Environment. Detection of environmental degradation products of nerve agents directly from the surface of plant leaves using static secondary ion mass spectrometry (sims) has been demonstrated (97). Pinacolylmethylphosphonic acid (PMPA), isopropylmethylphosphonic acid (IMPA), and ethylmethylphosphonic acid (EMPA) were spiked from aqueous samples onto philodendron leaves prior to analysis by static sims. The minimum detection limits on philodendron leaves were estimated to be between 40 and 0.4 ng/mm for PMPA and IMPA and between 40 and 4 ng/mm for EMPA. Sims analyses of IMPA adsorbed on 10 different crop leaves were also performed in order to investigate general apphcabiflty of static sims for... 

Presently available methods to diagnose and biomonitor exposure to anticholinesterases, e.g., nerve agents, rely mostly on measurement of residual enzyme activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in blood. More specific methods involve analysis of the intact poison or its degradation products in blood and/or urine. These approaches have serious drawbacks. Measurement of cholinesterase inhibition in blood does not identify the anticholinesterase and does not provide reliable evidence for exposure at inhibition levels less than 20 %. The intact poison and its degradation products can only be measured shortly after exposure. Moreover, the degradation products of pesticides may enter the body as such upon ingestion of food products containing these products. 

R.M. Black, R.J. Clarke, R.W. Read and M.T.J. Reid, Application of gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry to the analysis of chemical warfare samples, found to contain residues of the nerve agent sarin, sulfur mustard and their degradation products, J. Chromatogr., A, 662, 301-331 (1994). 

Nerve agents hydrolyze sufficiently slowly to be analyzed by LC/MS under reversed phase conditions. Although analyses for nerve agents alone are usually performed by GC-based methods, there are scenarios, for example, screening of water samples, in which LC/MS offers a rapid alternative. LC/MS is particularly useful for combined analysis of agents and degradation products. A number of applications have recently been reported for the... 

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