This study was conducted to investigate the residual behavior and safety assessment of fenazaquin and metaflumizone in butterbur. The samples were periodically harvested, extracted using QuEChERS method, and determined by LC-MS/MS. The linearity of matrix-matched calibration curve was ≥0.99 for both compounds. The average recoveries of fenazaquin and metaflumizone at two fortification levels (0.01 and 0.1 mg kg-1) ranged from 86.6 to 97.2%. The relative standard deviation was <10%. After 7 days, the fenazaquin and metaflumizone initial residues in butterbur were dissipated to 79 and 78%, with the respective half-lives, 3.08 and 3.15 days. The proposed preharvest intervals (PHIs) for fenazaquin is recommended as twice treatment 14 days before harvest and metaflumizone twice treatment 7 days before harvest of butterbur. Risk assessment showed that the acceptable daily intake of fenazaquin and metaflumizone in butterbur was 0.004 and 0.029%, respectively. The respective theoretical maximum daily intakes of fenazaquin and metaflumizone were 58.74 and 15.15%, indicating negligible risk.
Keywords: Insecticides; LC-MS/MS; PHI; minor-crops; safety assessment.