Mass spectrometry of benzo[a]- and benzo[c]acridines

The mass spectrograms of fourteen benzo[a]- and benzo[c]acridines, several of which are carcinogens, have been determined, and the following main features emerge: (a) presence of strong peaks corresponding to several stages of dehydrogenation; (b) very little fragmentation of the polycyclic frame, with, in ethylbenzacridines, a noteworthy splitting of methyl groups; and (c) importance of the double-charged ions, some of which contribute more to the ionic current than do the corresponding single-charged ones. The pattern of the spectrograms can vary considerably with the position of the substituents.