Determination of eight pesticides in cowpea by ultra performance liquid chromatography-tandem mass spectrometric

An ultra performance liquid chromatography tandem mass spectrometric method was established for the simultaneous determination the residues of 8 pesticides in Cowpea.The samples were processed by ultrasonic extraction with acetonitrile.The analysis was carried out by using electrospray ionization and ion monitoring components in the multiple reaction monitoring(MRM) modes,employing the external standard method.Under optimum conditions,the calibration curve was linear in the range of 0.01~0.50 mg/L and correlation coefficient r0.99.The limits of quantitation(LOQ) for the eight pesticides were 0.010 mg/kg.The average recoveries of 8 pesticides were 83.2% ～108.0% when the spiked levels were 0.02 mg/kg,0.05 mg/kg and 0.10 mg/kg,with relative standard deviations(RSDs) in the range of 1.1%～9.2%.The method was could be used as liable means for simultaneous quantitative determination.