LAUSR

BACKGROUND Methoxyfenozide possesses efficacy against to a variety of lepidopteron pests, including the major pests in cauliflower and tea, it is of great importance to generalize the practical use of methoxyfenozide in the field. RESULTS An efficient method was developed and validated in both vegetable matrix and extract-rich matrix (cauliflower and tea) using modified QuEChERS combined with UPLC-MS/MS analysis. The recoveries in cauliflower, made tea and tea shoots range from 94.5-108.0 %, 85.0-91.6 % and 77.3-82.0 % respectively, with the relative standard deviations (RSDs) below 17.3 % for all the cases. The field results showed that methoxyfenozide dissipated in cauliflower with the half-lives (t1/2 ) at 2.5-3.5 days, and in tea with t1/2 at 1.2 days. In combination of above experimental data and statistical food intake value, the risk quotient (RQ) values were significantly lower than 1. CONCLUSION The quantification method of methoxyfenozide in cauliflower or tea has not been established until this study. The dissipation and dietary exposure risk assessment of methoxyfenozide in cauliflower and tea were investigated in field. Methoxyfenozide dissipated rapidly in cauliflower despite of the different climates, and it dissipated faster in tea. The dietary risk of methoxyfenozide through cauliflower or tea was negligible to humans. This study not only provides guidance for the safe use of methoxyfenozide, but also serves as a reference for the establishment of maximum residue limits (MRLs) in China. This article is protected by copyright. All rights reserved.