Determination of 28 Kinds of Pesticide Residues in Tea by QuEChERS/Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

A QuEChERS/ultra performance liquid chromatography - tandem mass spectrometry(UPLC-MS/MS)method was developed for the determination of 28 kinds pesticide residues in green tea. The tested samples were extracted with 1% glacial acetic acid acetonitrile,and then purified using QuEChERS method. Analysis on the targets was performed by electrospray ionization mass spectrometry in positive mode,multiple reaction monitoring(MRM)mode was used for collection,and matrix matched standard curve method was selected for quantitation. Results showed that 28 analytes showed good linearities in their respective ranges,with correlation coefficients(r)between 0.990 and 0.998.The limits of detection(LOD,S/N≥3)were 0.08~1.26 μg/kg while the limits of quantitation(LOQ,S/N≥10)were 0.28~4.20 μg/kg. Recoveries for the target analytes at spiked levels of 10,50 and 80 μg/kg ranged from 72.5% to 118.5%,with relative standard deviations(n=6)of 0.8%~16.3%. The method is simple,rapid,replicable and high stable,and can satisfy meet the requirements for determination of 28 pesticide residues in tea.