Simultaneous determination of melatonin and pyridoxine in tablets by gas chromatography-mass spectrometry

A gas chromatographic-mass spectrometric (GC–MS) method for the qualitative and quantitative determination of melatonin plus pyridoxine commercial tablets is described. Melatonin and pyridoxine were simultaneously determined by GC–MS after extraction from ground tablets with methanol and derivatization with N-methyl-N-N-trimethlylsilyltrifluoroacetamide (MSTFA). The mass chromatograms were generated using 232 m/z ion for melatonin and 280 m/z ion for pyridoxine, respectively. Splitless injection offers good reproducibility with a standard deviation of 2%. The developed method was applied to analyze the melatonin and pyridoxine content from two different tablet formulations. Also, recovery, detection and quantification limits are reported.