Mass spectral analysis of synthones of nerve agents for verification of the Chemical Weapons Convention

Abstract

This communication describes the synthesis and gas chromatography/mass spectrometric (GC/MS) analysis of N,N-dialkylphosphoramidic dihalides and alkylphosphonic difluorides, which are synthones of nerve agents. The study was undertaken with a view to developing a spectral database of these compounds for verification purposes of the Chemical Weapons Convention (CWC). The modified synthetic approach reported here has advantages over traditional syntheses in terms of time and yield. GC/MS analysis of these synthones yielded electron ionization (EI) mass spectra and, based on these spectra, generalized fragmentation routes are proposed that rationalize most of the characteristic ions.

Gas chromatography/mass spectrometric analysis of methyl esters of N,N‐dialkylaminoethane‐2‐sulfonic acids for verification of the Chemical Weapons Convention

“…The ion with m/z 123 [8] was unexceptionally present in all compounds and produced the ion with m/z 79 [9] by elimination of C 2 H 4 O (Scheme 1). The molecular ion also fragmented by elimination of the alkyl radical from nitrogen (presumably in a charge-site initiation reaction followed by rearrangement of hydrogen, rH) producing ions [10] and [11].…”

“…The second important fragmentation mode was charge-site initiation from oxygen of the ester and nitrogen of the N,Ndialkylaminoethane linkage, which respectively produced the ions [7] and [8] with low relative abundances (entries 1-10 for ions [7] and [8], Table 1). The ion with m/z 123 [8] was unexceptionally present in all compounds and produced the ion with m/z 79 [9] by elimination of C 2 H 4 O (Scheme 1).…”

“…Since gas chromatography coupled with mass spectrometry (GC/ MS) is the widely used technique for identification of CWCrelated compounds, [17][18][19][20] a great deal of work is devoted to the development of a mass spectral database of these compounds. 8,9,[21][22][23][24] The chemicals relevant to the convention are enlisted in three schedules of an annex of the CWC. The categorization of chemicals in the three schedules is based on the toxicity, past use as CWAs, and commercial applicability of chemicals.…”

Gas chromatography/mass spectrometric analysis of N,N‐dialkylaminoethyl‐2‐chlorides and trimethylsilyl derivatives of N,N‐dialkylaminoethan‐2‐ols for verification of the Chemical Weapons Convention

“…The molecular ion fragmented by elimination of an alkyl radical (presumably in a charge-site initiation reaction followed by rearrangement of hydrogen, rH) producing ions [8] and [10], which then further fragmented to ions [9] and [11], respectively. These ions were indistinguishable from other ions for most of the compounds (Table 1, examples: entry 2 for ion m/z 92 [5] and [10], entry 3 for ion m/z 120 [3] and [5], entry 4 for ion m/z 92 [5] and [10] and entry 6 for ion m/z 106 [5] and [10]); hence, formation of these species cannot be confirmed in the EI-MS of these compounds.…”

“…Since gas chromatography coupled with mass spectrometry (GC/MS) is the most widely used technique for identification of CWC-related compounds (CRCs), [17][18][19][20] a great deal of work has been devoted to the development of a GC/MS database of these compounds. 8,9,[21][22][23][24] The chemicals of significance are listed in three schedules of an annex of the CWC. The categorization of the chemicals is based on their toxicity, past use as CWAs, and their commercial applicability.…”