An UHPLC-MS/MS method for the determination of antiparasitic drugs, including avermectins, in avian eggs, featuring a novel standard addition approach to validation

Antiparasitic drugs have widespread use in livestock to control parasitic infections. Their use can lead to residues in animal-derived food products, which can pose potential health risks to consumers. Therefore, a method has been developed for the semi-quantitative screening of 51 antiparasitic drug residues in avian eggs, using a QuEChERS based extraction method and analysis by UHPLC-MS/MS. This extension to coverage of these analytes also includes an approach to the analysis of the traditionally difficult avermectin class of analytes using source optimisation and post-column infusion. The method was validated according to CIR (EU) 2021/808 and the detection capability (CCβ) was set at 5 µg kg^-1 for all analytes, except fipronil and its metabolites, at 1.25 µg kg^-1. Additionally, a novel standard addition based confirmatory method for 10 analytes with MRL values was implemented, in accordance with EURL guidance.