Quantitative determination of thiabendazole in fruit juices and bulk juice concentrates using a thiabendazole monoclonal antibody

A thiabendazole [2-(4-thiazolyl)-1H-benzimidazole, TBZ] monoclonal antibody has been employed in an enzyme immunoassay (EIA) procedure to analyze TBZ in fruit juices and bulk juice concentrates. Samples were prepared by partitioning into methylene chloride and analyzed by EIA and HPLC. The average recovery for 50 juices and concentrates spiked at 5-1000 ppb was 93%. Forty-one market samples containing TBZ in the range from 0.6 to 280 ppb were analyzed, and the analyses by the two methods showed excellent agreement (r = 0.988). The detection limits were 0.5 ppb for juice and 2 ppb for bulk concentrates. Because a quicker and simpler sample preparation scheme would be desirable, seven positive juice samples were analyzed following direct dilution. For these samples, the correlation between EIA and HPLC was still very good (r = 0.92). Bulk juice concentrates generally required partitioning to completely eliminate matrix effects.