Separation and identification of some chemical warfare degradation products using electrospray high resolution ion mobility spectrometry with mass selected detection

Abstract

High resolution electrospray ion mobility spectrometry (IMS) was used to analyze chemical warfare degradation products from liquid samples. For each degradation product analytical figures of merit for the technique were determined and each response ion was identified by mass spectrometry. From these data, reduced mobility constants ( K 0) for a number of compounds were calculated for the first time. The detection limits for most of the compounds were less than 1 ppm in the positive mode. The more electronegative compounds such as the phosphonic acids were found to be more sensitive in the negative mode with detection limits in the low ppb range. This work represents the first published data of negative ion high resolution ion mobility spectrometry and is only the second publication in which negative ions have been produced and detected using atmospheric pressure electrospray ion mobility spectrometry. Linear response ranges were generally about two orders of magnitude and dynamic response ranges were approximately four orders of magnitude. Four degradation products from the G-type nerve agent differing only by a methyl group were separated with baseline resolution in less than 15 ms by IMS. This same mixture of components was separated and detected from a spiked Palouse river water sample demonstrating the potential of the technique to analyze chemical warfare degradation products from complex matrices. This represents the first quantitative study ever published for high resolution atmospheric pressure electrospray ion mobility spectrometry/mass spectrometry.