Application of capillary gas chromatography to the study of hydrolysis of the nerve agent VX in rat plasma

We present here a gas chromatography technique allowing the detection and quantification of VX [O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothiolate] as well as its P-S bond hydrolysis product diisopropylaminoethanethiol directly from spiked rat plasma. This technique was applied to study VX hydrolysis in rat plasma. We observed that 53+/-4% of 374 mu M VX disappeared from spiked plasma after 2 h. VX disappearance was mainly related to enzymatic cleavage of the P-S bond (K-m=2.5 mM and V-max=13.3 nmol min(-1) ml(-1) of rat plasma). The activity was totally inhibited by 1 mM Hg2+ and was also inhibited by metal chelators.