Gas chromatography/mass spectrometry analysis of reaction products of Chemical Weapons Convention–related 2‐(N,N‐dialkylamino)ethylchlorides with 2‐(N,N‐dialkylamino)ethanols

Abstract

RationaleThe Chemical Weapons Convention (CWC) mandates rigorous screening of chemical weapons and their potential degradation/reaction products, which is essential to identify such products in suspected samples. The reaction between 2‐(N,N‐dialkylamino)ethylchlorides and 2‐(N,N‐dialkylamino)ethanols (precursors/degradation products of VX agents) produces a new class of reaction products that are not explored.MethodsThe reaction products, bis(2‐N,N‐dialkylaminoethyl)ethers (1–10), were synthesized using established synthetic procedures, and gas chromatography/mass spectrometry (GC/MS) (electron ionization [EI] and chemical ionization [CI]) methods were developed for their identification. The GC/MS experiments were performed on an Agilent GC/MSD system using an HP‐5MS capillary column. Methane gas was used as the CI reagent gas for GC/CIMS experiments. GC/retention index (RI) values of 1–10 were calculated using the retention times of the hydrocarbon mixture and the analytes.ResultsThe GC/EI spectra of 1–10 exhibited [M‐H]+ ions and distinctive fragments that provided valuable structural information. The selective fragmentation of the alkyl groups on nitrogen facilitated the discrimination of possible isomeric compounds. Interpretation of EI fragments in the high mass region is important for unambiguous identification of 1–10, because the major ions significantly match other CWC‐related compounds containing the 2‐(N,N‐dialkylaminoethyl) group. GC/CI (methane) spectra included M+., [M + H]+, [M‐H]+, reagent‐specific adduct ions, and a few structure‐indicative fragments. The spiking experiments in soil and water samples revealed that the target analytes were stable, easily extractable, and detectable using GC/MS.ConclusionsThe reaction products, 1–10, could be successfully synthesized and characterized using GC/MS (EI and CI). The GC/MS and GC/RI data provide important insights into the unambiguous identification of the target molecules in challenging CWC verification and are helpful in participation in the Organization for the Prohibition of Chemical Weapons proficiency tests.