Quantification of plasma phenylethylamine by combined gas chromatography/electron capture negative ion mass spectrometry of the N-acetyl-N-pentafluorobenzoyl derivative

An ultrasensitive method capable of detection and quantification of beta-phenylethylamine in 1 ml of human plasma has been developed using gas chromatography/electron capture negative ion mass spectrometry. Phenylethylamine and tetra-deutero phenylethylamine internal standard in plasma were acetylated, extracted into organic solvent and then further acylated with pentafluorobenzoyl chloride. The N-acetyl-N-pentafluorobenzoyl-phenylethylamines were detected by high-resolution single ion monitoring of the molecular ions. Normal plasma levels were found to be 41.5 +/- 10.7 pg ml-1, in accordance with results of a previous high-performance liquid chromatographic method.