Abstract

Analytical methods with high sensitivity and accuracy were successfully validated for the quantification of 397 pesticides in different types of tea. For the UPLC-MS/MS method, 191 pesticides of 200 ones in total had “soft” matrix effects and could be quantified by calibration curves in the solvent. For the GC-MS/MS method, matrix-matched calibration curves were established on a mixed blank including white, green, oolong and black organic teas. The method limit of quantifications ranged from 1.0 µg kg−1 to 10 µg kg−1 (UPLC-MS/MS) and 1.0 µg kg−1 to 50 µg kg−1 (GC-MS/MS), with 70–120% of recovery. These methods was subsequently applied to 106 tea samples from several origins, in which 26 samples contained at least one pesticide violation, with a total of 43 pesticide residue violations. The most frequently detected pesticides were neonicotinoids, synthetic pyrethroids, and triazole fungicides. Taiwan had the most pesticide-contaminated samples followed by China, Vietnam, and India.

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