Metabolism of amphetamines. Identification of N-oxygenated products by gas chromatography and mass spectrometry

Abstract

A sensitive method for the isolation and identification of N-oxygenated metabolites and metabonates of medicinal amines is described. A combination of gas chromatography and mass spectrometry is effective in separating and identifying secondary hydroxylamines, oximes and nitrones, all of which are N-oxygenated products of secondary amines. These products give mass spectra containing diagnostic fragment ions which are of great value in identification. Primary hydroxylamines are oxidized on column to oximes and can be separated and identified as such. This oxidation is avoided if the primary hydroxylamine is introduced by direct inlet into the mass spectrometer. Secondary hydroxylamines are more stable during gas chromatographic examination although some decomposition to nitrone and secondary amine does occur. In contrast, oximes and nitrones show no tendency to decompose when gas chromatographed.