Development of a competitive ELISA based on estrogen receptor and weak competitive molecule for the screening of potential estrogens in foods.

Enzyme labeled competitive molecules are generally homologous with competitors in competitive broad-spectrum enzyme-linked immunosorbent assays (ELISA). It is speculated that the detectability will be improved when the competitiveness of competitive molecule is weak. Herein, common small molecule food hazard-estrogen disrupting chemicals (EDCs) were used as target model for verification. The dual-estrogen receptor (ER) and three estrogen-enzyme conjugates with various responses were used as recognizers and competitive molecules in ELISA. ELISA based on bisphenol (BPA)-horseradish peroxidase (HRP) has the highest detectability and can screen all six EDCs, in which BPA-HRP showed the weakest ER excitatory activity (Ka = 1.39 × 10-2 nmol·L-1) among three conjugates. The proposal showed good practicability with spiked recovery of 80.0-110 % for estrogens (17β-estradiol, 17α-estradiol, BPA) in foodstuffs, and revealed biomarkers with weak competitiveness may be applied to other competitive procedures to improve detectability, and it provides sensitive pre-screening strategy for follow-up screening tool.