Indirect competitive enzyme-linked immuno-sorbent assay (ELISA) for nitroimidazoles in food products

Ronidazole was used as the starting material to prepare an immunogen and coating antigen. An anti-nitroimidazole monoclonal antibody was produced and an indirect competitive ELISA was established to detect nitroimidazole compounds in food products. The IC(50) values were determined to be 0.20 ng/ml for metronidazole, 4.0 ng/ml for tinidazole, 0.17 ng/ml for dimetridazole and 0.24 ng/ml for ornidazole. Considering that nitroimidazoles were commonly used as veterinary drugs, nitroimidazole residues in food products of animal origin were detected by the method. The coefficient of variation for nitroimidazoles determination in contaminated chicken, chicken liver and shrimp were all <14% and the recovery rate was in the range 74.0-90.6%. The results proved that the developed method was successful in detecting nitroimidazoles in food products.