Mass spectral fragmentation pathways in some glycoluril-type explosives. A study by collision-induced dissociation and isotope labeling

Electron impact (EI), chemical ionization and negative-ion chemical ionization (NCI) mass spectra of 1,4-dinitroglycoluril (DINGU), its ¹⁵N- and ²H-labeled analogues and the dimethyl-substituted derivatives were recorded. Tandem mass spectrometry with collision induced dissociation was used to study the fragmentation pathways of these compounds. It was found that the main EI fragmentation processes of DINGU are due to the cleavage of C? N bonds and some rearrangement reactions.