Optimized LC–MS/MS method for simultaneous determination of multiclass veterinary anthelmintic residues in animal-derived matrices

Anthelmintics are veterinary drugs used to treat or prevent diseases in livestock and fishery products. However, their residues in animal-derived foods pose potential risks to human health. In Korea, maximum residue limits (MRLs) have been established to regulate such residues; however, for certain substances, including niclosamide, a widely used anthelmintic, only qualitative analytical methods are available, limiting effective residue monitoring. This study developed a multiresidue quantitative analytical method for 18 anthelmintic compounds. Method validation was conducted in accordance with CODEX guidelines (CAC/GL-71) using six livestock products (beef, pork, chicken, eggs, milk, and porcine fat) and three fishery products (flatfish, eel, and shrimp). Sample preparation was performed using the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction method followed by dispersive solid-phase extraction (d-SPE) clean-up. Simultaneous determination of the 18 anthelmintics was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The matrix-matched calibration curves exhibited coefficients of determination (R²) exceeding 0.99 for all target compounds. Furthermore, recovery rates at all target concentrations satisfied CODEX performance criteria, demonstrating acceptable accuracy and precision. The developed method can enhance the efficiency of residue analysis and provide a technical basis for establishing safety management standards for livestock and fishery products.