Simultaneous detection and identification of precursors, degradation and co-products of chemical warfare agents in drinking water by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

Environmental markers of chemical warfare agents (CWAs) comprise millions of chemical structures. The simultaneous detection and identification of these environmental markers poses difficulty due to their diverse chemical properties. In this work, by using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF), a generic analytical method for the detection and identification of wide range of environmental markers of CWAs (including precursors, degradation and co-products of nerve agents and sesqui-mustards) in drinking water, was developed. The chromatographic analysis of 55 environmental markers of CWAs including isomeric and isobaric compounds was accomplished within 20 min, using 1.8 μm particle size column. Subsequent identification of the compounds was achieved by the accurate mass measurement of either protonated molecule [M+H]+ or ammonium adduct [M+NH4]+ and fragment ions. Isomeric and isobaric compounds were distinguished by chromatographic retention time, characteristic fragment ions generated by both in-source collision induced dissociation (CID) and CID in the collision cell by MS/MS experiments. The exact mass measurement errors for all ions were observed less than 3 ppm with internal calibration. The method limits of detection (LODs) and limits of quantification (LOQs) were determined in drinking water and found to be 1-50 ng mL−1 and 5-125 ng mL−1, respectively. Applicability of the proposed method was proved by determining the environmental markers of CWAs in aqueous samples provided by Organization for the Prohibition of Chemical Weapons during 34th official proficiency test.