Determination of the hydrolysis products of nerve agents in natural waters by liquid chromatography--mass spectrometry

An approach to the determination of markers of the application of four nerve agents, S-(2- diethylaminoethyl)methylphosphonothioate, S-(2-diisopropylaminoethyl)methylphosphonothioate, bis(2-N,N- diethylaminoethyl)disulfide, and bis(2-N,N-diisopropylaminoethyl)disulfide, in aqueous environmental samples by high-performance liquid chromatography with tandem mass spectrometric detection (HPLC--[MS.sup.2]) is developed. The conditions of the mass spectrometric detection (selection of optimal pairs of ionic reactions) are optimized, and the program for the gradient elution in HPLC separation is adjusted. The proposed approach was tested in the analysis of real water bodies using the standard addition method. Good accuracy, reproducibility, and selectivity of determination were shown. It was demonstrated that the matrix components in the water samples have no interfering effect. Using the proposed approach, the detection limits of S-(2-diethylaminoethyl)methylphosphonothioate, S-(2-diisopropylaminoethyl)methylphosphonothioate, bis(2-N,N-diethylaminoethyl)disulfide, and bis(2-N,N-diisopropylaminoethyl)disulfide in water bodies, determined by HPLC--[MS.sup.2], were found to be 0.0003, 0.003, 0.3, and 0.05 µg [mL.sup.-1], respectively. Keywords: mass spectrometry, high-performance liquid chromatography, hydrolysis products of nerve agents VX and VR, analysis of waters DOI: 10.1134/S1061934815140105
INTRODUCTION The presence of S-(2-diethylaminoethyl)methylphosphonothioate (DEMP, degradation product of VR-gas), S-(2-diisopropylaminoethyl)methylphosphonothioate (DPMP, degradation product of VX-gas), bis(2-N,N-diethylaminoethyl)disulfide (DEAS, degradation product of VR-gas), and bis(2-N,Ndiisopropylaminoethyl)disulfide (DPAS, degradation product of VX gas) [...]