REACTIONS IN THE MASS-SPECTROMETRY OF A HYDRIDE MEISENHEIMER COMPLEX OF 2,4,6-TRINITROTOLUENE (TNT)

A hydride Meisenheimer complex of 2,4,6-trinitrotoluene (TNT) (TNTH-) was synthesized using tetramethylammonium octahydroborate. TNT and TNT H- (as the tetramethylammonium salt) were analyzed by direct exposure probe mass spectrometry using electron impact (EI), chemical ionizatio n (CI) and negative-ion chemical ionization (NCI). For further identif ication, the ions of the mass spectra were investigated using tandem m ass spectrometry with collision-induced dissociation (CID). Although t he Fl mass spectra of both compounds were similar, the CID mass spectr a of the ions at mit 227 (M(+) of TNT) of the two compounds showed lar ge differences in daughter ion abundances. A major difference between the two compounds also appeared in their CI methane mass spectra. Two abundant ions, at m/z 183 and 198, appeared only in the CI mass spectr um of TNTH-. CID parent ion scans showed that the origin of these two ions was not the mit 227 ion. We suggest that these ions are formed by chemical reactions of the complex on the surface of the heated probe tip, followed by ionization. These reactions, probably a reduction pro cess forming mit 198 and hydrolysis forming mit 183, occur preferentia lly in TNTH-, the already reduced form of TNT. Formation of the ions a t m/z 183 and 198 was also observed in the liquid chromatography parti cle beam CI mass spectrum of TNTH-.