Characterization of equimolar VX-water reaction product by chromatography mass spectrometry

One method proposed for the destruction of the chemical warfare nerve agent VX, O-ethyl S-2-(diisopropylamino)ethyl methylphosphonothiolate, is hydrolysis by the addition of an equimolar amount of water. To better understand this reaction, a method was developed for characterization of the resulting product and for monitoring product stability. Conditions for derivatization of the acidic products to their trimethylsilyl esters, with subsequent analysis by gas chromatography-mass spectrometry using electron (EI) and methane chemical ionization (CI) were optimized to allow nonchromatographable acids and organic products to be detected in a single analysis, without loss of volatile products, and with minimal side reaction. EI and methane CI mass spectra of 23 identified degradation products are provided. Results indicate that the product is relatively stable at ambient temperatures in a closed container with only a minimal amount of thiol secondary reaction being observed. Published by Elsevier Science B.V.