Residue levels and dietary risk assessment of fluopimomide, pyraclostrobin and its metabolite BF-500–3 in garlic ecosystems under field conditions

To evaluate the residue levels of fluopimomide, pyraclostrobin and its metabolite BF-500–3 in garlic ecosystems, supervised garlic field trials with a commercial formulation (pyraclostrobin·fluopimomide 30% suspension concentrate (SC)) were conducted in six regions of China according to the Good Agricultural Practices (GAP). The residues of fluopimomide, pyraclostrobin and BF-500–3 in field samples were determined using a QuEChERS method combined with high-performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS). The average recoveries of all target compounds were 76–94% with relative standard deviations (RSDs) of 1.0–14.5% and limits of quantitation (LOQs) of 0.002 mg/kg. At the recommended pre-harvest interval (PHI, 10 days), the residues of fluopimomide, pyraclostrobin and BF-500–3 were below 0.16, 0.77 and 0.12 mg/kg in garlic chive; below 0.027, 0.22 and 0.002 mg/kg in garlic scape; and below 0.002, 0.002 and 0.002 mg/kg in garlic, respectively. Dietary intake risks were calculated using risk quotients (RQs) based on field residual data, toxicological data and dietary patterns. The chronic dietary risk quotients (RQc) of pyraclostrobin and fluopimomide were 48.42% and 0.36%, respectively. The acute dietary risk quotients (RQa) of pyraclostrobin in garlic were 0.06–0.15%. These results indicated a low dietary risk for consumers. This study could provide scientific guidance for the application of pyraclostrobin and fluopimomide in garlic.