Effective Monitoring of Fluxapyroxad and Its Three Biologically Active Metabolites in Vegetables, Fruits, and Cereals by Optimized QuEChERS Treatment Based on UPLC-MS/MS.

Qualitative analysis and quantification of pesticide residues in foodstuff are essential to our health in daily life, especially regarding their metabolites, which may be more toxic and persistent. Thus, a valid analytical measure for detection of fluxapyroxad and its three metabolites (M700F002 (C-2), M700F008 (C-8), M700F048 (C-48)) in vegetables (cucumber, tomato, and pepper), fruits (grape, apple), and cereals (wheat, rice) was developed by UPLC-MS/MS with negative ion mode. The target compounds were extracted by acetonitrile contain 0.2% formic acid (v/v), and the extractions were cleaned up by octadecylsilane sorbents. The limits of quantitation and quantification were less than 0.14 μg kg-1 and 0.47 μg kg-1 in seven matrices. Furthermore, recoveries at levels of 0.01, 0.05, and 0.1 mg kg-1 ranged from 74.9% to 110.5% with relative standard deviations ≤15.5% (n = 5). The method is validated to be effective and robust for the routine supervising of fluxapyroxad and its metabolites.