Graphene-based pipette tip solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry for determination of ten lipophilic shellfish toxins in shellfish

: A method for the simultaneous determination of ten lipophilic shellfish toxins was established based on graphene-based pipette tip solid-phase extraction (G-PT-SPE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The factors influencing the extraction efficiency, including the types of extractants, the amount of graphene, the types and volumes of washing and eluent solvents, were optimized in detail. Under the optimal conditions, the calibration curves showed linear relationships between the LC peak areas of the selected ion-pairs and the mass concentrations of the ten lipophilic shellfish toxins with correlation coefficients >0.99. The limits of detection (LODs) and the limits of quantification (LOQs) of the method were 0.1-1.1 μg/kg and 0.3-3.2 μg/kg, respectively. The recoveries of the ten lipophilic shellfish toxins spiked in blank oyster at three levels ranged from 72.0% to 101.2% with relative standard deviations <15%. The method is sensitive, simple, and effective, and is suitable for the determination of the lipophilic shellfish toxins in shellfish products.