Synthesis of haptens and production of antibodies to bisphenol A

Abstract

Three immunizing haptens of bisphenol A (BPA), including two new haptens, were used to produce highly sensitive and specific polyclonal antibodies. The spacer arms of haptens for coupling to the protein carrier were located at different positions in BPA, and different length spacer arms were tested. Highly sensitive polyclonal antibodies were obtained and characterized using indirect competitive enzyme-linked immunosorbent assay (icELISA). Under optimized conditions, the half maximal inhibitory concentration (IC50) value of the best polyclonal antibody was 2.1 mg·L−1, based on coating heterogeneous antigens, and this optimal polyclonal antibody was highly sensitive toward BPA and displayed negligible cross-reactivity with bisphenol B and bisphenol E. A sensitive icELISA method utilizing the polyclonal antibody was developed for the determination of BPA in milk. In spiked samples (5, 10 and 20 mg·L−1), the recovery ranged from 80% to 102% with a coefficient of variation (CV) value below 15.8%. The limit of detection of icELISA was 1.95 mg·L−1. These results indicate that the icELISA method is suitable for the detection of BPA in milk.

Keywords

• bisphenol A|cross-reactivity|hapten|indirect competitive ELISA|polyclonal antibody