Flow injection fluorimetric determination of β-estradiol using a molecularly imprinted polymer

The steroidal compound 17β-estradiol (E2) is a major estrogen now widely studied because of its potential endocrine disruption effects. The present paper describes a simple, rapid, flow injection (FI) method for the fluorimetric determination of β-estradiol involving a molecularly imprinted polymer (MIP) packed into a microcolumn. Microwave-assisted extraction, a relatively new technique, was used to help remove the template from the MIP; this improved extraction efficiency. The optimization of the FI parameters and the intrinsic fluorescence of β-estradiol allowed its direct determination without a derivatization step. When the possible interference of other estrogens was examined, the system displayed excellent specificity for β-estradiol; no response to the natural estrogens estrone and estriol and the xenoestrogen bisphenol A was recorded. Under optimum experimental conditions, linear calibration graphs were obtained from 4 to 80 µg L−1 with a detection limit of 1.12 µg L−1.