Quantification of pesticide residues in vegetables by gas chromatography with tandem mass spectrometry after dispersive-solid phase extraction

Objective: A quick method was developed for the determination of 49 pesticide residues in vegetables by gas chromatography with tandem mass spectrometry(GC-MS/MS) after dispersive solid-phase extraction.Methods: The target compounds were extracted from the samples with ethyl acetate and the extracted solution was cleaned up using dispersive solid-phase extraction.The collected solution was analyzed by GC-MS/MS.The target pesticides were confirmed by using timed SRM with two transitions of each targets and quantified by internal standard method.Results: In the linear range(0.01 mg/L~10.0 mg/L) of each pesticide,the correlation coefficient was higher than 0.99.The average recoveries(spiked at the levels of 0.01 mg/kg,0.02 mg/kg) were from 70.8%~122.5%.The relative standard deviations were from 0.7%~7.8%(n=6),and all limits of quantification(LOQs) were less than 10 μg/kg.Conclusion: The method is quick,sensitive,accurate,reproducible and suitable for the analysis of pesticide residues in vegetables.