Rapid Determination of Metolcarb Residues in Foods Using a Biomimetic Enzyme-Linked Immunosorbent Assay Employing a Novel Molecularly Imprinted Polymer Film as Artificial Antibody

A novel and fast competitive direct biomimetic ELISA (cd-BELISA) was developed for determination of the N-methylcarbamate insecticide metolcarb based on a molecularly imprinted polymer (MIP) film as the antibody mimic. The MIP film was directly synthesized on the surface of a 96-well plate by bulk polymerization. The synthesized film was characterized, and the results showed that the imprinted film exhibited antibody-antigen-like binding properties and rapid adsorption ability, which was particularly useful for cd-BELISA development. The cd-BELISA conditions were optimized in detail. Under the optimum conditions, the sensitivity and LOD of the cd-BELISA were found to be 17 and 0.12 mu g/L, respectively. Cross-reactivity demonstrated that the cd-BELISA had a higher selectivity for metolcarb than for structurally related compounds. The developed method was applied to the determination of metolcarb in spiked apple juice, cabbage, and cucumber, with mean recoveries ranging from 71.5 to 117.0%. Validation of the results was conducted by HPLC with good correlation (r(2) > 0.9562) between data obtained using these two methods. Therefore, the developed cd-BELISA has potential for the rapid determination of metolcarb in foods.