A novel method to detect seven microcystins in hard clam and corbicula fluminea by liquid chromatography–tandem mass spectrometry

A simple and reliable method to detect seven microcystins in hard clam and corbicula fluminea, based on liquid chromatography with electrospray ionization and tandem mass spectrometry (LC–ESI-MS/MS), was developed and validated. The sample preparation procedure includes extraction of tissue by methanol, followed by cleanup on a reversed-phase solid phase extraction (SPE) cartridge. With the optimized method, recoveries were between 43.7% and 92.3% for hard clam, 54.3% and 93.8% for corbicula fluminea, the relative standard deviations (RSD) were less than or equal to 16.2% and 15.7% in hard clam and corbicula fluminea at spiking levels of 1 μg/kg, 2 μg/kg and 5 μg/kg for MC-RR, MC-YR, MC-LR, and MC-LY, and 2 μg/kg, 5 μg/kg and 10 μg/kg for MC-LA, MC-LW and MC-LF, respectively, the limits of quantitation (LOQ) of this method were ranged from 0.7 μg/kg to 2.0 μg/kg.