Determination of chemical warfare agents, their hydrolysis products and related compounds in soil

Abstract

A procedure based on sequential hexane and dichloromethane extraction followed by trimethylsilyl derivatization and capillary column gas chromatographic-mass spectrometric (GC-MS) confirmation was developed for the verification of chemical warfare agents, their hydrolysis products and related compounds in soil. The chemical warfare agents sarin, soman and mustard and the simulant triethyl phosphate were added to four different soil types at the 50 and 5 μg/g levels and recovered with efficiencies varying from nearly 100% to about 5%. The recovery efficiencies were in the range 50–90% for most soil types contaminated with soman, mustard and triethyl phosphate. Sarin recovery was generally the lowest (5–30%). Hydrolysis products, due to degradation of the spiked chemical warfare agents during the course of the experiments, were detected and confirmed as trimethylsilyl derivatives. The developed sample handling and analysis procedure was applied to soil samples in support of range clearance operations. The chemical warfare agent tabun and sixteen related components and their hydrolysis products were identified during capillary column GC-MS analysis of soil extracts.