Determination of melatonin in pharmaceutical formulations and human plasmaby gas chromatography-electron impact mass spectrometry

A simple and reliable method for gas chromatography-mass spectrometry (GC-M S) has been developed for the determination of melatonin in commercially av ailable tablet formulations and human plasma. The dissolution of the tablet s in ethyl acetate was simply obtained by sonication. The filtrate of the r esultant solution, after concentration, was derivatized with pentafluoropro pionic anhydride (PFPA) and analysed by GC-MS using splitless injection. Th e linear response range for melatonin was 5-250 ng on column. The same meth od can be used, with minor modifications, for the determination of melatoni n in spiked human plasma in the range 50-1000 pg/mL plasma. Copyright (C) 1 999 John Wiley & Sons, Ltd.