Fragmentation pathways of chemical weapons convention-related organophosphorus Novichok agents: The electron ionization and electrospray ionization tandem mass spectroscopy and DFT calculation studies

Abstract

To unambiguously identify the chemicals associated with the Chemical Weapons Convention (CWC) in environmental samples, knowledge on mass spectral data, interpretive skills, and rapid microsynthesis of suspected agents are essential. The mass spectral data of a new group of Novichok organophosphorus nerve agent derivatives have been studied for the confirmatory purposes of the CWC. These compounds' fragmentation pathways were proposed and discussed via electron ionization (EI) and positive electrospray ionization (+ESI) methods. The MS analysis of the deuterated analogs and Density Functional Theory (DFT) calculations were performed to confirm the fragmented structures. Several new fragmentations and rearrangements have been observed. Theoretical analyses were also conducted by the DFT method using the B3LYP functional and 6-311+G (d, p) basis set on two Novichok derivatives (A-230 and A-232). Structural, electronic and thermodynamic data were calculated by the computational methods and interpreted. The findings from this study should be helpful to detect CWC-related chemicals during on-site and/or off-site inspection.