One-step SPE-UHPLC-MS/MS for simultaneous detection of fenbendazole and metabolites in animal-derived foods.

Fenbendazole (FBZ) is a highly effective antiparasitic agent widely used in veterinary medicine; however, its improper application can lead to residues in edible animal-derived products, posing potential health risks to humans through accumulation via the food chain. This study aimed to establish an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of FBZ and metabolites in animal-derived foods. The proposed method involves a one-step solid-phase extraction followed by UHPLC-MS/MS analysis for the simultaneous detection of FBZ, oxfendazole, and oxfendazole sulphone. The method demonstrated excellent linearity, with correlation coefficients (R2) exceeding 0.99. The limit of detection and limit of quantification were 2.0 μg/kg and 5.0 μg/kg, respectively. Average recoveries ranged from 85.0% to 108.4%, with relative standard deviations below 10%. The established method is simple, highly specific, and sensitive, offering a reliable approach for production monitoring, routine batch analysis, and confirmatory testing of FBZ and metabolites in animal-derived foods.