Mass spectral studies of N-oxides of chemical weapons convention-related aminoethanols by gas chromatography/mass spectrometry after silylation.

N-Alkylaminoethanols, N,N'-dialkylaminoethanols, and triethanolamine are the hydrolyzed products or precursors of V-agents/nitrogen mustards. These compounds are prone to undergo oxidation in environmental matrices. Detection of the oxidized products provides a clue for the presence of parent amine compounds and it is an important task in the verification process of chemical weapons convention. Gas chromatography/mass spectrometry is the technique of choice for the detection of most of the chemical warfare agents; however, it is ideal to develop gas chromatography/mass spectrometry techniques for all the possible degradation products of chemical warfare agents as well. In general, the N-oxides of amines are expected to be thermally unstable; hence, the gas chromatography/mass spectrometry analysis of the N-oxides of triethanolamine, N-alkyldiethanolamines and N,N'-dialkylaminoethanols is not explored. In this study, the N-oxides of chemical weapons convention-related aminoethanols (13 compounds) were successfully silylated and then analyzed by gas chromatography/mass spectrometry under electron ionization and chemical ionization techniques. The electron ionization mass spectra showed abundant molecular ions and structure indicative fragment ions including [M-(O+CH2CH2OH)]+. The alkyl groups attached to nitrogen resulted in structure-specific fragment ions that enable differentiation of isomeric compounds. The methane/chemical ionization spectra showed considerably abundant [M+H]+ (>10%) and the expected adduct ions. The retention indices of all the compounds were calculated using Van den Dool's formula. The gas chromatography/mass spectrometry data together with retention index values could be used for unambiguous identification of the N-oxides of aminoethanols during off-site analysis or proficiency tests.

Mass spectral studies on vinylic degradation products of sulfur mustards under gas chromatography/mass spectrometry conditions.

Sulfur mustards are a class of vesicant chemical warfare agents that rapidly degrade in environmental samples. The most feasible degradation products of sulfur mustards are chloroethyl vinylic compounds and divinylic compounds, which are formed by the elimination of one and two HCl molecules from sulfur mustards, respectively. The detection and characterization of these degradation products in environmental samples are an important proof for the verification of sulfur mustard usage. In this study, we synthesized a set of sulfur mustard degradation products, i.e., divinylic compounds (1-7) and chloroethyl vinylic compounds (8-14), and characterized using gas chromatography/mass spectrometry (GC/MS) under electron ionization (EI) and chemical ionization (CI) (methane) conditions. The EI mass spectra of the studied compounds mainly included the fragment ions that resulted from homolytic cleavages with or without hydrogen migrations. The divinylic compounds (1-7) showed [M-SH](+) ions, whereas the chloroethylvinyl compounds (8-14) showed [M-Cl](+) and [M-CH2CH2Cl](+) ions. Methane/CI mass spectra showed [M+H](+) ions and provided molecular weight information. The GC retention index (RI) values were also calculated for the studied compounds. The EI and CI mass spectral data together with RI values are extremely useful for off-site analysis for the verification of the chemical weapons convention and also to participate in official Organization for the Prohibition of Chemical Weapons proficiency tests.