Development of an immunoassay for carbendazim based on a class-selective monoclonal antibody

In the present study, a class-selective monoclonal antibody (mAb) for carbamate fungicides was obtained using two haptens. One hapten was designed as immunogen and the other one for coating. Under the optimum assay conditions of coating antigens H2-ovalbumin, in the assay buffer of sodium chloride 1.6%, no methanol, and pH 6.5, the assay system was more sensitive. The linear range was from 0.06 to 7.47 ng/mL. The cross-reactivity test was carried out with IC50 values of 0.45 ng/mL for carbendazim, 0.57 ng/mL for benomyl, and 9.70 ng/mL for thiabendazole. Other related compounds thiophanate methyl, fenbendazole, mebendazole, methyl paraoxon, methyl parathion, chlorpyrifos, and chlorothalonil did not cross-react significantly in this assay. To evaluate the proposed immunoassay, real samples such as apples, tomatoes, and cucumbers were subjected to recovery test with carbendazim. The recovery and coefficient variation range from 73% to 125% and 0.36% to 11.80%, respectively. The developed method was also compared with the commercial kit for assaying carbendazim in the fruits and vegetables and the results were consistent. All results indicated that this developed enzyme-linked immunosorbent assay (ELISA) is useful for the detection of carbendazim residues in fruits and vegetables.