Packed capillary liquid chromatography-electrospray mass spectrometry analysis of organophosphorus chemical warfare agents.

Packed capillary column liquid chromatography (LC)-electrospray mass spectrometry (ESI-MS) was used for the first time to detect and identify four common organophosphorus chemical warfare agents in aqueous samples. Aqueous samples containing the organophosphorus chemical warfare agents in the 0.01 to 0.1 mg/ml range were analyzed directly by packed capillary LC-ESI-MS with the chemical warfare agents and several minor related impurities being well resolved under acetonitrile-water gradient elution conditions. The ESI-MS data for isopropyl methylphosphonofluoridate (sarin or GB), O-ethyl N,N-dimethylphosphoramidocyanidate (tabun or GA), cyclohexyl methylphosphonofluoridate (GF) and pinacolyl methylphosphonofluoridate (soman or GD) were acquired with a sampling cone voltage setting that promoted collisionally activated dissociation, and resulted in the acquisition of informative mass spectra containing both molecular and product ion information. The developed method appears to be an attractive alternative to GC-MS for the analysis of aqueous samples containing organophosphorus chemical warfare agents and their hydrolysis products, since they may be analyzed directly without the need for additional sample handling.