Determination Of Bisphenol A By Enzyme Linked Immunosorbent Assay

Bisphenol A (BPA), generally known as Endocrine Disrupting Chemicals(ECD), had a potential estrogenic characteristic. In recent years, Bisphenol A has been found in food plastic packaging materials. The content of BPA is much lower either in the environment or in the food packaging materials, it cannot be analyzed rapidly by general HPLC. The rapid method for determination bisphenol A(BPA) was carried out by ELISA in this paper, which will be beneficial to food safety supervision and technique storage.Bisphenol A hapten (BPAH) was prepared by the method of diazotization, and then it was coupled to carrier protein bovine serum albumin (BSA) and ovalbumin (OVA) to prepare immunogen BPAH–BSA and coating antigen BPAH–OVA. UV scanning spectrum and IR spectrum both indicated that the immunogen BPAH–BSA and coating antigen BPAH–OVA were successfully synthesized. The coupling rates were 12.2 and 13.2 respectively by ultraviolet spectrophotometry analysis. New Zealand rabbits were immunized with BPAH–BSA and the highest titer of serum was as high as 51200. Then, an indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed. The detection limit was 0.001μg·mL-1, and IC50 value (50 % inhibitory concentration) was 10μg·mL-1. The reproducibility was estimated by coefficient of variation (CV %). The coefficient of variation were 4.07～9.95 %, all below 10 %.The specificity was studied with cross reactivities using four similar chemical structure compounds (4,4-bis(4-hydroxyphenyl) valeric acid,bisphenol B,bisphenol E and 4-cumyphenol). The cross reactivities were 20.0 %, 10.0 %, 3.3 %, 2.0 %, respectively. BPA was added to drinking water and the recoveries were 92.5～107.7 %. In general, all indexes of the assay have reached the requirements of detection, and it showed that this assay had potential application in practice.