Two-dimensional MS/MS scans on a linear ion trap mass analyzer: Identification of V-Series chemical warfare agents

Abstract Chemical warfare agents (CWAs) are devastating weapons of terror due to their highly lethal and dispersive nature. Powerful analytical tools are required to help create a knowledge base that will contribute to preventing attacks using these agents. Highly sensitive measurements must be made quickly with high selectivity for a wide range of potential molecular targets. Portable mass spectrometers have emerged as a robust platform for in-situ detection of chemical threats. However, due to size, weight, and power constraints, they are typically limited to a single mass analyzer with limited MS/MS capabilities, most notably the provision of full scan and product ion MS/MS spectra. Here we demonstrate the application of a new, highly efficient scanning methodology that uses a single linear quadrupole ion trap to acquire two-dimensional mass spectrometry data (2D MS/MS). With only a single scan, we show that it is possible to acquire mass-to-charge information on V-series chemical warfare agents– namely,: (1) Ethyl ({2-[bis(propan-2-yl)amino]ethyl}sulfanyl)(methyl)phosphinate (V1), (2) N , N -diethyl-2-(methyl-(2-methylpropoxy)phosphoryl)sulfanylethanamine (VR), (3) O-Butyl S-[2-(diethylamino)ethyl] methylphosphonothioate (VX) and (4) S-[2-(Diethylamino)ethyl] O-ethyl methylphosphonothioate (VM) - as precursors while simultaneously (in the same scan) acquiring product ion spectra for each CWA via mass spectral microfeatures. For mixtures of V-series agents, 2D MS/MS is a time- and sample-efficient method for obtaining MS/MS data. Discussed here are advantages and limitations of 2D MS/MS compared to conventional data-dependent product ion MS/MS scans.