Fate and dietary risk assessment of pyriproxyfen, dinotefuran, and its metabolites residues in tomato across different regions in China.

Registration of a new formulation called 30% suspension concentrate (30% SC, pyriproxyfen 10% + dinotefuran 20%) to inhibit the occurrence of whitefly in tomato is currently under review in China, so it is necessary to research the residue behavior and dietary risk of pyriproxyfen and dinotefuran in tomato under field conditions. According to Good Agricultural Practices (GAP), the formulation was sprayed once at the dosage of 112.5 g a.i./ha (active ingredient/hectare) at the initial stage of the occurrence of tomato whitefly and the recommended pre-harvest interval (PHI) for sampling was 5 days. Meanwhile, the residues of pyriproxyfen, dinotefuran, and the metabolites of dinotefuran in tomato samples were determined using QuEChERS (quick, easy, cheap, effective, rugged, and safe) and high-performance liquid chromatography-tandem mass spectrometry. The results showed that the terminal residue levels of the analytes detected in tomato samples were below 0.19 mg/kg for pyriproxyfen and 0.25 mg/kg for dinotefuran at the recommended PHI (5 days), which were lower than the maximum residue limits of China. The dietary risk assessment was also carried out based on field trial results, toxicological data, and Chinese dietary pattern. Both the chronic risk quotients (≤ 26.59%) and acute risk quotients (≤ 1.14%, general population, > 1 year) of pyriproxyfen and dinotefuran were far below 100%, indicating a low risk to consumers' health. The paper will be conducive to provide guidance for the rational application of these insecticides on tomato.