Abstract
This study examines the dissipation and residue behavior of fluopyram, trifloxystrobin, and their metabolites (fluopyram-benzamide and trifloxystrobin acid, CGA 321113) in grapes grown in Al-Qassim, Saudi Arabia. The fungicide Luna Sensation® 500 SC (250 g/L fluopyram, 250 g/L trifloxystrobin) was applied at the recommended rate (100–150 g a.i./ha). A multi-residue LC-MS/MS method was developed and validated according to SANTE 11312/2021 guidelines, demonstrating high linearity (R² > 0.999), low detection limits (0.00021–0.00094 mg/kg), and recoveries of 84.8–94.8% with RSDs < 20%. Dissipation studies revealed first-order kinetics, with fluopyram exhibiting faster degradation (t1/2 = 2.23–3.02 days) than trifloxystrobin (t1/2 = 3.46–4.04 days). CGA 321113 dissipated to below detectable levels within 3 days, while fluopyram-benzamide remained undetected. Terminal residues were below the maximum residue limits (MRLs) of 3 mg/kg (trifloxystrobin) and 2 mg/kg (fluopyram), with pre-harvest intervals of 6.29 and 2.13 days, respectively. Chronic dietary risk assessments confirmed negligible health risks and provided valuable insights for effective pest management and the safe use of pesticides in Saudi grape cultivation.