Preparation of monoclonal antibody and development of an indirect competitive enzyme-linked immunosorbent assay for ornidazole detection

•A sensitive and specific ic-ELISA was established for ONZ detection.•The IC50 value of the mAb was 0.15 µg/kg.•An ic-ELISA of ONZ was verified with HPLC method.

A monoclonal antibody (mAb) and an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for ornidazole (ONZ) detection were developed. ONZ was conjugated with cationic bovine serum albumin as a hapten to generate the artificial immunogens and coating antigens. BALB/c mice were immunized, and mAbs were obtained. The competitive inhibition curve of ic-ELISA was y = 0.0438x2 − 0.2101x + 0.2925, with R2 = 0.9941. The 50% inhibition concentration, the limit of detection, and limit of quality for ONZ were 0.15, 0.01, and 0.05 µg/kg, respectively. The cross-reactivity of the mAbs to secnidazole was 0.33%. The recoveries were from 89.18% to 101.63% and the coefficient of variation was less than 7.15% in chicken, chicken liver, and honey samples, all of which had ONZ concentrations of 0.05 and 0.1 μg/kg. Results showed that the ic-ELISA based on mAb could be used for the rapid detection for ONZ.