MONOCLONAL ANTIBODY-BASED ELISA FOR THIABENDAZOLE IN LIVER

An enzyme-linked immunosorbent assay (ELISA) was developed for analysis of thiabendazole [2-(4-thiazolyl)-1H-benzimidazole, TBZ] residues in bovine liver. Monoclonal antibodies which bind TBZ and 5-OH-TBZ were developed using the haptens, 2-(2-succinamido-4-thiazolyl)benzimidazole and 5-succinamido-2-(4-thiazolyl)benzimidazole. The ELISA method uses monoclonal antibody in a competitive format, following a one-step, 10-min aqueous extraction of samples. Monoclonal antibodies with various specificities permit an ELISA specific for TBZ alone or for the group of thiazolyl compounds including TBZ, 5-OH-TBZ, and cambendazole. Tissue samples of 0.1 g can be used, and the limit of detection, determined by analysis of liver samples fortified with TBZ, is 20 ppb. The extraction and assay can be completed within 2 h. The assay materials are sufficiently stable to be packaged as a kit with a shelf life of at least 6 months. ELISA results were validated by comparison to results obtained by high-pressure liquid chromatography with UV detection. Since samples exceeding the U.S. tolerance (100 ppb) can readily be distinguished from negative samples simply by visual inspection of the ELISA wells, the method provides a rapid screening test which could be used for regulatory monitoring of TBZ residues in meat.