Analyte sarin

There are no measurements of the actual concentrations of diisopropyl methylphosphonate in groundwater at the RMA during the years of active production of the nerve gas Sarin (i.e., 1953-1957) (EPA 1989). The first actual measurements of the concentration of diisopropyl methylphosphonate in the groundwater on the arsenal and surrounding property to the north and west were made in 1974 (Robson 1981). The concentrations of diisopropyl methylphosphonate in the groundwater ranged from 0.5 g/L (analytical detection limit) to as much as 44,000 g/L near the abandoned waste disposal ponds. Diisopropyl methylphosphonate was discharged into a lined reservoir at the RMA in 1956 and was still present 20 years later in concentrations of about 400,000 g/L (Robson 1977). 

Dialkyl alkylphosphonates are of interest as analytes for a number of reasons. They may be present as impurities in nerve agents, and as such may be useful indicators of use or production as they are much more stable in the environment an example is diisopropyl methylphosphonate found in sarin. Dialkyl methylphosphonates may be formed in decontamination reactions of nerve agents in basic formulations containing alcohols or cellusolves. They are also important precursors to nerve agents, for example, dialkyl methylphosphonates are converted to the key... 

A validated method for IMPA and PMPA in reaction masses was also reported (30). After neutralization of GB (sarin) and GD (Soman) with aqueous monoethanolmine, IMPA and PMPA were determined through spiking. Linear calibration was achieved for both analytes over a range of 0.5-100 xg/ml. Intraday precision based on peak area ranged from... 

After Pronase digestion of plasma, the analytes were concentrated on a C18 or C8 cartridge and analyzed by LC/MS/MS. The adducts have been detected in the blood of guinea pigs 24 h after being exposed to 0.5 LD50 doses of sarin and soman. It is not known if they are formed in cases of human exposure. 

One piece of evidence supporting the efficacy of PAM in sarin toxicity has been the clinical benefit associated with PAM in toxicity due to organophosphorous agrochemicals. However, some experts now doubt whether such a benefit really exists. For example, Peter et al (2006), using meta-analytic techniques, reevaluated the effects of oxime therapy in organophosphate poisoning. Not only did they find no beneficial effects, they also reported possible... 

Application of well-known chemical agents in terrorist acts as complex compositions with other compounds may significantly to hamper their identification in the air and on the ground with use of usual analytical methods. In this case we can expect that clinical course of intoxication of victims will be atypical and curing effect of known antidotes and other medications will be brought to nothing. Practical confirmation of such application of chemical agent in terrorist purposes with use of sarin took place in Japan (Matsumoto, 1994 Tokyo Subway, 1995). 

Separation of the various stereoisomers of the nerve agents for analytical purposes became feasible with the advent of optically active coating materials for columns as used in capillary gas chromatography (GC) and in high performance liquid chromatography (HPLC). The complete separation of the four stereoisomers of soman and of the two stereoisomers of sarin with GC on capillary columns is described in Section III. So far, (-1-)- and (-)-VX could not be separated by means of capillary gas chromatography, but HPLC on a so-called Chiralcel OD-H column yields complete separation of the two stereoisomers of this agent. ... 

When properly installed, the analytical system involving thermodesorption cold trap injection and two-dimensional chromatography can be used routinely for analysis of the stereoisomers of soman and sarin in blood and tissue samples at minimum detectable concentrations of 1 -5 pg of stereoisomer per ml blood or gram tissue. In recent toxicokinetic experiments in pigs, the analytical system comprised chiral gas chromatography on a Chirasil-L-Val column with splitless injection and detection... 

The combined use of acidification to pH 4, addition of alnminnm snlfate and of neopentyl sarin, proved to be sufficient to stabilize the stereoisomers of sarin and soman. In snbsequent work-up, the analytes and internal standard are extracted from the stabilized blood or tissue sample by means of solid-phase extraction and elntion with ethyl acetate, for gas chromatographic analysis. The same work-np and analytical procednre can be used for homogenized brain and diaphragm tissne samples. 

The active site of organophosphorus hydrolase (OPH) contains two metal atoms (zinc in the wild-type enzyme) and catalyzes hydrolysis of numerous organophos-phate compounds including pesticides as well as chemical warfare agents such as sarin and soman. Rates of OPH catalyzed hydrolysis of organophosphates exceed those of chemical hydrolysis by NaOH at 4°C by factors of 40 to 2450 [41-43]. The enzyme has been described for use in sensor systems with exceptional detection limits reported for response times on the order of 10 seconds [44-48]. However, the presence of OP/CWA is detected by the inhibition of enzymatic rate determined by comparing rate measnrements in the presence and absence of the analyte. 

Rapid detection of chemical warfare agents in the field is essential. However, reliable analytical techniques such as gas or liquid chromatography are not suitable for routine use out of the laboratory. One method that has been investigated makes use of the release of HF from the hydrolysis of a fiuorophosphonate compound (e.g. Sarin). The reaction is catalysed by a copper(II) complex containing the MezNCHzCHzNMez ligand ... 

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