Detection, chemical warfare

Applications GC-IMS is applied only in a few laboratories. Most applications have been directed toward environmental analyses. GC-IMS is used in niche areas, such as high-speed air-quality monitoring (on board space stations) and detecting chemical warfare agents. Snyder et al. [319] have described a hyphenated field-portable hand-held GC-IMS device, which was applied to the separation of phosphate (TMP, TEP)/phosphonate (DMMP, DEMP, DIMP, DEEP) mixtures. A mixture of four phosphonate analytes can be successfully resolved with a small GC-IMS device in under 8 s. 

APD 2000 A portable, hand-held chemical detection and monitoring device that detects chemical warfare agents, recognizes pepper spray and Mace, and identifies hazardous compounds. 

There have been many quite useful discoveries in chemistry and chemical engineering over the years that have been used for detection applications. The first example is plasma chromatography, otherwise known as ion mobility spectrometry. In the 1980s this technique became the method of choice for detecting chemical warfare agents and was used by soldiers in Desert Storm with unfortunate results. Official reports tell that the rate of false alarms for these instruments was so high that soldiers became desensitized to real hazards. One infantry battalion eventually turned their alarms off. Much of the Gulf War Syndrome may well have been caused because ion mobihty spectrometry was oversold as a detection technique. 

Recently, IMS devices have become comparatively small and effective devices to determine traces of quantities of VOCs down to the low ppby range, especially in air [19]. The major advantages of IMS are that no vacuum system is required for operation and ambient air can be used as a carrier gas. Worldwide, more than 70000 units are in service, especially to detect chemical warfare agents, narcotics and explosives, and many different instruments are available on the market [20, 21]. It was shown that VOCs are detectable at the nanogram, and sometimes picogram, per h-ter levels in air [22-37]. 

Evaluation of current Hazmat and EMS chemical detection equipment for ability to detect chemical warfare agents. 

Sielemann, S. Baumbach, J.I. Schmidt, H., IMS with non radioactive ionization sources suitable to detect chemical warfare agent simulation substances, Int. J. Ion Mobil. Spectrom. 2002, 5, 143-148. 

There are more approaches to the analysis of chemical warfare agents than just the chromatographic or mass spec-trometric based techniques. These include nuclear magnetic resonance spectroscopy (NMR) or spectrophotometric detection. Additional approaches similar to GC, LC and MS are capillary electrophoresis (CE) and ion mobility spectroscopy (IMS). This chapter describes the instrumentation used to analyse and detect chemical warfare agents, from the simplest of techniques to the more complex, which allow for precise and accurate detection at very low levels. The authors have tried to be as comprehensive as possible in outlining the various methods utilized however, it is understood that because of the implications of GW As, there may be proprietary or classified methods, not yet in the public domain. 

Brinkley et al. demonstrated89 a simple to use, easy to interpret, low cost, and environmentally friendly colorimetric detector of the chemical warfare agent - mustard gas (HD, l,l-thiobis(2-chloroethane)). An optically transparent xerogel encapsulating Cu(II) acetate was fabricated to detect HD analogues and can serve as the optical sensor based on metal-ligand charge-transfer mechanism. 

The detector model is capable of simulating both vapour and liquid detection systems. So far, about a dozen different detector systems are available. The detector model input signal (see 2.1) consists of i) a time concentration profile, ii) the identity of the chemical warfare agent (HD, GB, VX or L) and iii) the relative air humidity (RH < 80% or RH > 80%). 

ACN and DCM are also known to be chemical warfare agent (CWA) simulants. ACN is a known simulant for blood CWAs, while DCM is a simulant for choking CWAs49 50. For determinations of ACN and DCM as CWA simulants, the detection limits need to be improved51. Such improvements may be possible by the application of more stable light source and detector to reduce noise in the measured signal. 

Tomchenko, A. A. Harmer, G. P. Marquis, B. T., Detection of chemical warfare agents using nanostructured metal oxide sensors, Sens. Actuators B. 2005, 108,41 55... 

SABRE 2000 The portable SABRE 2000, using a scanning system based on IMS (Ion Mobility Spectrometry) can detect drugs, explosives, and chemical warfare agents. More than forty substances can be simultaneously detected and identified in seconds. 

Lightweight Chemical Detector (LCD-S) The LCD-S acts as a local warning alarm system for individuals and small groups of persons within the domestic or military market. It simultaneously detects, identifies, and differentiates between type of chemical warfare agent at below attack concentration, and warns users when to don personal protective equipment. 

Ionscan CENTURIAN Detection System This system provides fixed site continuous ambient air monitoring for chemical warfare agents and toxic industrial chemicals. 

M272 Water Testing Kit A lightweight portable kit used to detect and identify dangerous levels of common chemical warfare agents in raw and treated water in about seven minutes. It is a test water sampler and is not a continuous monitor. Each kit includes twenty-five tests for each agent. 

MOCVD as, 22 153-154 in silicon carbide fiber manufacture, 22 534 thermally activated, 24 744-745 Chemical vapor infiltration (CVI), 26 767 ceramics and, 5 664 Chemical warfare, 5 813-840 defense against, 5 830-837 Chemical warfare agents, detection of, 22 716-717... 

A wide variety of commercial equipment is available for detection of hazardous chemicals, including a number of chemical warfare agents. For example, ion mobility spectroscopy is used to detect nerve, blister, and blood agents. The Chemical Agent Monitor is a portable, hand-held point detection instrument that uses ion mobility spectrometry to monitor nerve or blister agent vapors. However, minimum detection limits are approximately 100 times the acceptable exposure limit for nerve agents, and approximately 50 times the acceptable exposure limit for blister agents. 

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