Establishment of a QuEChERS-UPLC-MS/MS Method for Simultaneously Detecting Tolfenpyrad and Its Metabolites in Tea

Abstract

An analytical method simultaneously detecting pesticide and its metabolites, especially with higher toxicity, was urgently needed for supervision and safety evaluation of agricultural products. In the present study, a modified QuEChERS method coupled with a ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for simultaneous determination of tolfenpyrad (TFP) and its metabolites in tea matrices (fresh tea shoots, green tea, black tea, green tea infusion and black tea infusion) was established. The method validation showed good linearity (correlation coefficients ≥ 0.9945), accuracy (recoveries in 75.38–109.90%), sensitivity (limits of quantification ≤ 0.05 mg kg−1), and precision (relative standard deviations ≤ 19.09%). The established method was then applied to detect 40 market samples, resulting in 60.0% positive rate of TFP, besides, two metabolites including PT-CA, which is more toxic than the parent TFP, and PT-OH were also detected in the samples with high TFP residue (≥0.048 mg kg−1). The method established in the present work was thus of significant importance in comprehensive monitoring and of TFP in tea products.