Determination of 22 pesticide residues in shellfish by high performance liquid chromatography-tandem mass spectrometry

A method for the simultaneous determination of 22 pesticide residues in shellfish by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The pesticides in the samples were extracted with 0.1% (v/v) formic acid in acetonitrile, cleaned up with primary secondary amine (PSA) and graphitized carbon black (GCB), and then separated on an ACE UltraCore 2.5 Super C18 column (100 mm×2.1 mm, 2.5 μm) by elution with a methanol-0.1% (v/v) formic acid solution at a flow rate of 0.4 mL/min. The analytes were detected by electrospray ionization in the positive ion mode and the multiple reaction monitoring mode. Good linear relationships were obtained, and the correlation coefficients (r2) of the 22 pesticides were all higher than 0.997. The limits of detection and limits of quantification were 0.1-0.3 μg/kg and 0.3-1.0 μg/kg, respectively. The mean recoveries varied from 65.2% to 109.4% at three spiked levels, and the relative standard deviations ranged from 1.3% to 15.2% (n=6). The proposed method is simple, accurate, and sensitive, and is effective for the simultaneous determination of 22 pesticide residues detected in shellfish.