Preparation of an anti-4,4′-dinitrocarbanilide monoclonal antibody and its application in an immunochromatographic assay for anticoccidial drugs

This study outlines the successful development and testing of an immunochromatographic test strip for the detection of the anticoccidial drug, nicarbazin in milk. The preparation and characterization of an anti-4,4′-dinitrocarbanilide monoclonal antibody was based on hapten re-4,4′-dinitrocarbanilide. The monoclonal antibody was highly specific for 4, 4′-dinitrocarbanilide, with a half-life inhibitory concentration (IC50) of 3.46 ng/mL. The detection limit was 0.86 ng/mL. The linear range was 1.71–7 ng/mL. The cut-off values of colloidal gold-based immunochromatographic test paper in phosphate buffered saline (PBS) and in milk were 10 ng/mL, 100 ng/mL, respectively. These results were in good agreement with ELISA analyses and suggest that immunochromatographic test strips are a fast and sensitive method for the semi-quantitative and qualitative analysis of nicarbazin in milk.