Integrated assessment of sulfindoflufen and its major metabolite residues in citrus: Field dissipation, processing factors, and probabilistic dietary risk evaluation.

Abstract

Sulfindoflufen, a novel aryl trifluoroethyl sulfoxide acaricide, has demonstrated exceptional efficacy against tetranychid mites; however, the lack of data regarding its environmental persistence and metabolic fate poses a significant challenge for regulatory oversight. This study presents the first comprehensive investigation into the residue behavior of sulfindoflufen and its primary metabolite (YDMF-M1) in citrus through a multi-center field-to-consumer framework. A validated Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction coupled with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) enabled simultaneous quantification of sulfindoflufen and YDMF-M1 across multiple citrus matrices, with recoveries of 73-109% and relative standard deviations (RSDs) below 16.9%. Twelve field trials across four major production regions in China showed moderate dissipation, with half-lives ranging from 16 to 17 days and terminal residues ≤ 0.14 mg/kg. By elucidating the metabolic relationship between sulfindoflufen and YDMF-M1, we confirmed the metabolic conversion is minimal under field conditions, with the parent compound remaining the predominant residue. Industrial processing studies further showed substantial residue reduction: washing removed 61-77% of residues; juicing resulted in processing factors (PFs) of 0.048-0.061; pomace retained modest residues (PF = 0.126-0.150); and no detectable residues were found in citrus oil. Both deterministic and probabilistic dietary risk assessments indicated negligible chronic exposure risks. The 97.5th percentile (P97.5) and 99.9th percentile (P99.9) chronic dietary exposures were ≤ 46.432% and ≤ 81.178% of the acceptable daily intake (ADI), respectively. Conceptually, this study provides a comprehensive residue-to-risk evaluation paradigm for novel acaricides lacking metabolic data, offering a robust scientific basis for establishing national