Enantiomeric profiling of mefentrifluconazole in watermelon across China: Enantiochemistry, environmental fate, storage stability, and comparative dietary risk assessment

Abstract Elucidating the enantiomeric chemistry and enantioselective fate of the novel chiral triazole fungicide mefentrifluconazole is of vital importance for agroecosystem safety and human health. The absolute configuration of mefentrifluconazole was identified firstly as S-(+)-mefentrifluconazole and R-(−)-mefentrifluconazole on a cellulose tris(3-chloro-4-methylphenylcarbamate) chiral phase. A baseline resolution ( Rs , 2.51), favorable retention ( RT ≤ 2.24 min), and high sensitivity (LOQ, 0.5 μg/kg) of enantiomer pair were achieved by reversed-phase liquid chromatography tandem mass spectrometry combined with a 3D response surface strategy. Nationwide field trials were undertaken to clarify the enantiomer occurrence, enantioselective dissipation, terminal concentrations, and storage stability of S-mefentrifluconazole and R-mefentrifluconazole in watermelon across China. The original deposition of the sum of enantiomer pair was estimated to be 14.4–163.7 μg/kg, and terminally decreased to