An electrochemical ELISA procedure for the screening of 17beta-estradiol in urban waste waters

A sensitive electrochemical enzyme-linked immunosorbent assay (ELISA) has been used for the detection of 17beta-estradiol in waste waters. The activity of the label enzyme (horseradish peroxidase) was measured electrochemically using 3,3',5,5'-tetramethylbenzidine as electrochemical substrate. The detection limit was estimated to be 5 pg mL(-1), interday and intraday precision (RSD), ranged from 1 to 3% and from 3 to 6%, respectively. Analysis of waste waters from three different treatment plants demonstrated no matrix effect both for samples diluted 1:1 in buffer and diethyl ether extracted. Data on 36 samples analysed by an LC-ESI-MS-MS procedure and by the electrochemical ELISA assay were compared. Results correlated well. The electrochemical enzyme immunoassay appears suitable as a screening tool for analysis of estradiol in waste waters.