Residue Dynamics of Metaflumizone in Tomatoes and Peppers Using LC–MS/MS: Pre-Harvest Intervals and Dietary Risk Assessment

Peppers (<i>Capsicum annuum</i> L.) and tomatoes (<i>Solanum lycopersicum</i> L.) are staple vegetables of considerable economic and nutritional importance. However, their production faces challenges from pest infestations and diseases, particularly in intensive cultivation systems. This study aimed to develop and validate a method for analyzing <i>EZ</i>-metaflumizone, a novel sodium channel-blocking insecticide, using acetonitrile for extraction and LC-MS/MS for quantitation in peppers and tomatoes. Method optimization improved sensitivity, effectively minimizing matrix effects (ME: -2.72% for tomatoes and -9.43% for peppers). Validation demonstrated recoveries ranging from 77.2 to 94.1%, with precision (RSD) below 20%, and a limit of quantification (LOQ) of 0.005 mg/kg, which is well below the EU maximum residue limits (MRLs) of 1.5 mg/kg for peppers and 0.7 mg/kg for tomatoes. The dissipation kinetics of E/Z-metaflumizone (24% SC) were studied under greenhouse conditions following application at recommended and double recommended doses. The half-lives of metaflumizone residues were 2.99-3.14 days in tomatoes and 3.47-3.53 days in peppers, with dissipation following first-order kinetics. Preharvest intervals (PHIs) were determined to be 2.69-5.82 days for tomatoes and 1.86-3.4 days for peppers. Dietary exposure and hazard quotient (HQ) values indicated negligible risk to adult consumers, with HQs ranging from 8.37 to 28.05% for tomatoes and 18.15 to 41.20% for peppers. These findings provide valuable insights into residue behavior, risk assessment, and dissipation kinetics, which can inform authorities' decision-making for high-value crops.