Abstract: A method for the determination of melamine in cosmetics was developed by hydrophilic interaction chromatography-tandem mass spectrometry (HILIC-MS/MS). The sample was extracted in turn by aqueous solution of trichloroacetic acid and hexane, and then cleaned-up by the mixed-mode cation exchange (MCX) solid-phase extraction (SPE) cartridge. A ZIC-HILIC column was used for the separation by gradient elution, and an electrospray ion trap mass spectrometer was used in the positive ion mode. The linear range of melamine was from 0.02 mg/L to 0.5 mg/L with a correlation coefficient of0.9985. The limit of detection (LOD, S/N≥3) and limit of quantification (LOQ, S/N＞10) were 5.0 μg/kg and 20.0 μg/kg, respectively. The average recoveries and the relative standard deviations ranged from 84.7% to 93.4% and from 4.5% to 8.4%, respectively, in spiked samples at the concentrations from 0.01 mg/kg to 0.1 mg/kg. The method is suitable for the determination of melamine in cosmetics.

Key words: cosmetics, melamine, residue, hydrophilic interaction chromatography-tandem mass spectrometry (HILIC-MS/MS)