Determination of 80 Pesticide Residues in Vegetables and Fruits by Liquid Chromatography-Tandem Mass Spectrometry

A liquid chromatography-tandem mass spectrometric(LC-MS/MS)method was developed for the simultaneous determination of 80 pesticides of different chemical classes(mainly including organophosphorous compounds,acetanilide herbicide and carbamates)in vegetables and fruits.The sample was extracted with acetonitrile,and cleaned up by PSA and C18 columns.80 pesticides were separated on a C18 column(1.8 μm,100 mm×2.1 mm i.d.)using 0.1% formic acid and 5 mmol/L ammonium acetate in water(A)-acetonitrile(B)as mobile phase in gradient elution.The analytes were detected with positive-ion electrospray ionization-mass spectrometry in dynamic multiple reaction monitoring(Dynamic MRM)mode.Under the optimal conditions,the linear ranges for all the pesticides were over 3 orders of magnitude with correlation coefficients not less than 0.99.The detection limits(LODs)ranged from 0.02 to 3 μg/kg(S/N=3).The recoveries of 80 pesticides were measured from samples of different fruits and vegetables.The results showed that the mean recoveries of 80 pesticide residues at two spiked concentration levels of 0.01 and 0.05 mg/kg were in the range of 64%-118% and 72%-108%,respectively,with relative standard deviations(RSDs)of 3.7%-29.1% and 3.4%-27.9%,respectively.The method was rapid,sensitive,reliable,and could be used to analyse the pesticide residues in a wide variety of fruits and vegetables.