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.