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] a 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 μM 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 of rat plasma). The activity was totally inhibited by 1 mM Hg²⁺ and was also inhibited by metal chelators.