MASS-SPECTRAL FRAGMENTATION PATHWAYS OF N-ACETYLNITRAMINES - 1-ACETYLHEXAHYDRO-3,5-DINITRO-1,3,5-TRIAZINE AND 1-ACETYLOCTAHYDRO-3,5,7-TRINITRO-1,3,5,7-TETRAZOCINE

Mass spectra of the N-acetylnitramines 1-acetylhexahydro-3,5-dinitro-1,3,5-triazine (TAX) and 1-acetyloctahydro-3,5,7-trinitro-1,3,5,7-tetrazocine (SEX) were recorded in electron impact (EI) and positive and negative chemical ionization (PCI and NCI) modes, and the fragmentation pathways were compared with those of other nitramines which have been well documented and characterized. Unexpectedly, for both acetylnitramines in the EI mode (and in the PCI mode) proton adducts were the only molecular ion species observed; in neither mode was there evidence for higher adducts. In contrast, for TAX in the NCI mode the [M + NO2]- adduct was the second most abundant ion (70%); relatively small amounts of the [M + NO]- adduct (2%) and the hydrogen adduct [MH]- (3%) were observed. Under identical NCI conditions no molecular ion species or adduct ions were detected for SEX; the ion of highest m/z corresponded to loss of NO2 or HNO2 from a molecular ion species. The findings of collision-induced dissociation experiments are also discussed.