An ion‐trap mass spectrometric study on electron impact and collisionally induced decomposition pathways of some phenothiazine S‐oxides

The electron ionization (EI) mass spectra and the daughter-ion spectra of the EI-generated main fragments of phenothiazine S-oxides and its two N-substituted derivatives have been studied by means of ion-trap mass spectrometry (ITMS). Interesting differences with the data already published on the same molecules as obtained by a magnetic sector instrument have been rationalized by considering how, under ITMS conditions, charge exchange or self-chemical-ionization phenomena can take place, leading to molecular species with low energy content.