A qualitative screening method for 17 coccidiostats in eggs and animal muscle by QuEChERS-UPLC-MS/MS validated according to Regulation (EU) 2021/808.

Coccidiostats are veterinary drugs commonly used in poultry livestock to treat and prevent coccidiosis, a severe and widespread parasitic infections in the industry. In the European Union, several coccidiostats are authorized as feed additives for poultry and laying hens, which may lead to residues in muscle tissues and eggs. The aim of this study was the development and validation, compliant with Commission Implementing Regulation (EU) 2021/808, of an qualitative screening method for the determination of seventeen coccidiostats in eggs and animal muscle tissues using a QuEChERS extraction approach combined with UPLC-MS/MS. The method achieved Detection Capability (CCβ) of 1 μg kg⁻¹ for fourteen coccidiostats (amprolium, halofuginone, clopidol, decoquinate, diclazuril, nequinate, nicarbazin, maduramicin, monensin, lasalocid, narasin, robenidine, salinomycin, and semduramicin) and 10 μg kg⁻¹ for toltrazuril and its metabolites (toltrazuril-sulfone and toltrazuril-sulfoxide). Validation was performed on muscle tissues from different animal species (cattle, chicken, sheep, and swine) and on chicken eggs, in accordance with the cited Regulation. The method proved to be robust, reliable, and specific, making it suitable for application in official control laboratories.