Analytical Sciences

Quantitative Measurement of 17beta-Estradiol and Estriol in River Water by Time-Resolved Fluoroimmunoassay

Keisuke MAJIMA,* Takashi FUKUI,* Jingli YUAN,** Guilan WANG,** and Kazuko MATSUMOTO* 

*Department of Chemistry, Waseda University, Advanced Research Institute for Science and Engineering, Shinjuku, Tokyo 169-8555, Japan
**Department of Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116012, P. R. China

A sensitive method for detecting 17beta -estradiol (E2) and estriol (E3) in river water has been developed, based on the time-resolved fluoroimmunoassay by using a fluorescent europium chelate label, 4,4'-bis(1,''1'',1'',2'',2'',3'',3''-heptafluoro-4'',6''-hexanedion-6''-yl)-chlorosulfo-o-terphenyl (BHHCT)-Eu³⁺. In the E2 assay, microtiter plates were coated with the E2-bovine serum albumin (BSA) conjugate. The anti-17beta -estradiol antibody, the biotinylated goat anti-rabbit IgG antibody and the BHHCT-Eu³⁺ labeled streptavidin (SA)-BSA conjugate were used. In the E3 assay, the goat anti-rabbit IgG antibody was coated on a microtiter plate. The anti-estriol antibody and the BHHCT-Eu³⁺ labeled E3-BSA conjugate were used. The detection limits for E2 and E3 were 2.3 pg/ml and 4.3 pg/ml, respectively, and the analytical recoveries were 95 - 120%. Quantitative measurement of estrogens in river water was carried out for Kanda River (Tokyo, Japan) by using the method. The E2 and E3 levels were 32 pg/ml and 5.5 pg/ml, respectively. The detection limits of the present method are in the same orders of magnitude as those of ELISA for E2, and are 1 - 2 orders of magnitude better for E3.

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