Abstract: Ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with solid phase extraction (SPE) has been developed for the determination of 7 microcystins (MCs) in Spirulina health food products. The sample was extracted by 70% (v/v) methanol. The lipid substances were isolated by centrifugation under freezing condition, and then followed by clean-up with a Waters Oasis HLB solid phase extraction cartridge. The separation was performed on a Waters ACQUITY UPLCBEH C18 column with gradient elution using acetonitrile and 0.2 mmol/L ammonium acetate. The electrospray ionization (ESI) source in positive ion mode was used for multiple reaction monitoring (MRM). The external standard method was used for the quantification. The linear ranges for 7 MCs were 20-400 μg/kg, and the correlation coefficients were not less than 0.995. The limits of detection were 6.7-33.3 μg/kg. The limits of quantification were 20.0-100.0 μg/kg. The recoveries of the 7 MCs spiked in blank Spirulina samples ranged from 87.5% to 97.9% with the relative standard deviations of 1.6%-6.9%. The results demonstrated that the method is easy, fast, sensitive, and suitable for the confirmation and quantification of the 7 MCs in Spirulina samples.

Key words: microcystins (MCs), Spirulina health food products, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), solid phase extraction (SPE)