Capillary GC-MS determination of melatonin in several pharmaceutical tablet formulations.

A simple capillary GC-MS method for the determination of melatonin from tablets is proposed. Melatonin (N-acetyl-5-methoxytryptamine) was determined by gas chromatography-mass spectrometry after extraction from ground tablets with ethyl acetate and derivatization with N-methyl-N-trimethylsilyl-heptafluorobutyramide (MTSHFBA). Splitless injection offers good reproducibility with a standard deviation of +/- 2%. The proposed method was applied to analyse the melatonin content from three different tablet formulations.