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International Journal of Analytical Chemistry
Volume 2011, Article ID 214747, 8 pages
http://dx.doi.org/10.1155/2011/214747
Research Article

Optimization of Molecularly Imprinted Polymer Method for Rapid Screening of 17β-Estradiol in Water by Fluorescence Quenching

Department of Chemistry, Carleton University, Ottawa, ON, Canada K1S 5B6

Received 21 January 2011; Revised 3 May 2011; Accepted 16 May 2011

Academic Editor: Stig Pedersen-Bjergaard

Copyright © 2011 Yu Yang and Edward P. C. Lai. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A new method was optimized for rapid screening of 17β-estradiol (E2) in water under 10 min. Molecularly imprinted polymer (MIP) particles (325 ± 25 nm) were added in a water sample at pH 5.5 and 20C to form a suspension. Fluorescence emission from E2 nonspecifically bound onto the MIP particles was first quenched by large gold nanoparticles (43 ± 5 nm). The Stern-Volmer plot was linear, with dynamic quenching constants (Ksv) of 2.9 ×104 M-1. Fluorescence emission from E2 specifically bound inside the MIP particles was next quenched by small nitrite anions that easily penetrated the imprinted cavities. The Stern-Volmer plot became nonlinear, with Ksv = 2.1 × 102 M-1 and static quenching constant (V) below 1.0 M-1. The difference between these two emission intensities varied as the initial E2 concentration in water, generating a Scatchard calibration curve with R2>0.97 from 0.1 to 10 ppb.