Metabolism of phenothiazines: identification of N-oxygenated products by gas chromatography and mass spectrometry.

The solid inlet mass spectra of the N-oxide and N-oxide sulphoxide metabolites of promazine, chlorpromazine and methotrimeprazine have been determined at different temperatures and compared with the mass spectra of the main thermolytic product of the N-oxides and N-oxide sulphoxides obtained during combined gas chromatography-mass spectrometry. Diagnostic ions were produced by direct insertion of the compounds at ambient temperature into the mass spectrometer. These ions distinguish the N-oxides of arylalkyl tertiary amines from the N-oxygenated derivatives of primary and secondary arylalkylamines.