Screening organophosphorus nerve agent degradation products in pesticide mixtures by GC-ICPMS

Abstract

Gas chromatography inductively coupled plasma mass spectrometry (GC-ICPMS) was utilized for the analysis of four organophosphorus nerve agent degradation products in the presence of mixtures of common organophosphorus pesticides. The first degradation products of sarin (isopropyl methylphosphonic acid, GB acid), cyclosarin (cyclohexyl methylphosphonic acid, GF acid), and soman (pinacolyl methylphosphonic acid) as well as their common final hydrolysis product methyl phosphonic acid were utilized throughout these experiments. Due to the non-volatile nature of these alkyl phosphonic acid degradation products, derivatization was performed to generate the volatile tert-butyl dimethylsilyl species. Degraded organophosphorus pesticide standards were obtained for acephate, chlorpyrifos, dichlorvos, ethion, and parathion ethyl. Mixtures consisting of three pesticides in the presence of a single nerve agent degradation product were prepared. GC-ICPMS allowed for the separation and detection of all four degradation products in the presence of pesticide mixtures in just over 12 minutes. This is the first study analyzing pesticides as interfering species for analysis of nerve agent degradation products by GC-ICPMS.