Formation of Mass Spectra of Positive and Negative Ions of Trinitrotoluene Isomers under the Gas Chromatography Mass Spectrometry Conditions

For the six isomers of trinitrotoluene the processes of chromatographic separation and formation of mass spectra of positive and negative ions have been studied by means of gas chromatography/mass spectrometry (GC-MS). The mass spectra of positive ions were obtained under the standard electron ionization mode at 70 eV. The resonant electron capture negative ionization mass spectra were obtained in the regime of continuous rapid variation of electron energy in the low-energy range 0–10 eV. Analysis of the ionic composition of the positive ionization mass spectra showed that the most fragmentary ions originate from the migration of the methyl hydrogen atom toward an adjacent nitro group causing the formation of [M – OH]+ ions. Negative ions formation, in contrast, proceeds predominantly via nitro-nitrite rearrangements followed by removal of NO- and/or NO2-groups.