Validation of an immunoassay for fast screening of bisphenol A in canned vegetables
The effects of BPA exposure on human health are an issue of concern and controversy. In the present work, the validation for the first time of a monoclonal antibody-based enzyme-linked immunoassay (ELISA) for BPA determination in canned vegetables is described, using HPLC as the reference method. From a collection of monoclonal antibodies, a high-sensitivity immunoassay was selected on the basis of its tolerance to organic solvents and the influence of matrix effects. This ELISA displayed a limit of detection of 3 μg kg−1 of BPA in the whole product of canned vegetables and 15 μg L−1 of BPA in the liquid portion. For assay validation, processed vegetables were fortified with BPA at 10, 50, and 200 μg kg−1. Sample treatment rendered crude and purified extracts. Purified extracts were analyzed by HPLC and ELISA, while crude extracts could be analyzed only by ELISA. Depending on the crop and the fortification level, good recoveries were obtained for both methods: 70.6–105% for HPLC and 61.4–115% (purified extracts) or 82–120% (crude extracts) for ELISA. HPLC was more precise than ELISA. Finally, crude extracts of canned peas were analyzed by ELISA. Results (33–62 μg kg−1) also compared well with those obtained by HPLC on purified extracts (23–44 μg kg−1). In all samples, BPA concentration was significantly lower than the specific migration level of 600 μg kg−1 established by the European Commission. Therefore, the ELISA herein validated constitutes a sensitive, fast, and high-throughput technique for BPA screening in canned vegetables.