Development of an indirect competitive chemiluminescent enzyme immunoassay for ethanamizuril residue detection in eggs and feed

Ethanamizuril (EZL), a newly developed antiparasitic drug, is expected to be widely used in poultry production in the future, but its residues in eggs and feeds pose potential risks to food safety. This study developed an indirect competitive chemiluminescent enzyme immunoassay (ic-CLEIA) for the quantitative detection of EZL residues in eggs and feeds. By optimizing the reaction conditions, the ic-CLEIA achieved a sensitivity (half-maximal inhibitory concentration, IC 50 ) of 0.12 ng/mL and a linear range (IC 20 –IC 80 ) of 0.02–0.92 ng/mL. Both the intra-assay and inter-assay coefficients of variation were less than 12%, demonstrating excellent reproducibility and high agreement with HPLC–MS/MS results. The developed ic-CLEIA filling the gap in rapid trace detection of EZL residues, provides a reliable technical support for food safety supervision of EZL residues, and expands the application of CLEIA in veterinary drug residue detection.