Positive and negative ion mass spectrometry of benzophenones, the acid-hydrolysis products of benzodiazepines

Positive electron impact (EI), positive chemical ionization (CI), and negative CI mass spectra of 14 benzophenones are presented. In the positive EI mode, intense molecular peaks appeared for most compounds; some other peaks due to splitting at both sides of the carbonyl group also appeared. In the positive CI mode, [M + 1]+ quasi-molecular ions together with [M + C2H5]+ peaks were observed for all compounds; some fragment peaks were common to those in the positive EI mode. In the negative CI mode, the spectra were much simpler than those in the positive EI or CI mode. In the 1 Torr negative CI mode, some spectra showed only single molecular anions; in the 0.01 Torr negative CI mode, halogen or nitro peaks appeared in addition to the molecular anions. An extraction procedure for benzophenones from human urine and plasma after heating in strong acid, and their separation by gas chromatography (GC) are also presented to serve for their actual identification by GC/mass spectrometry.