Rapid Determination of Organonitrogen, Organophosphorus and Carbamate Pesticides in Tea by Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS)

A rapid and effective multiresidue method has been developed for the determination of 18 pesticide residues (selected from organonitrogen, organophosphorus, and carbamate pesticides) in tea by ultrahigh-performance liquid chromatography-tandem mass spectrometry. Tea samples were extracted with acetonitrile and purified by a novel multilayer solid-phase extraction cartridge-Cleanet TPT. Evaluation of the influence of the mobile phase on the ionization efficiency, resolution, and sensitivity was carried out by comparing the acetonitrile-water and methanol-water with different modifiers. The recoveries of all the pesticides varied from 70 to 110 % with a relative standard deviation of less than 15 %, and the determination coefficient for each pesticide was R (2) > 0.99. Matrix-matched standard calibration curve was used to reduce errors associated with matrix-induced enhancement or suppression effects. The limit of detection for all targeted pesticides ranged from 0.03 to 1.5 mu g/kg. Applicability of this analytical approach was confirmed by successful determination of tea samples from different regions of China.