▎ 摘　　要

A ratiometric electrochemical sensor has been developed for highly sensitive and selective detection of bisphenol A. The assay strategy was based on the competitive host-guest interaction between poly-beta-cyclodextrin/electroreduced graphene (P beta-CD/EG) and Rhodamine B (RhB) probe or bisphenol A (BPA) target molecules. RhB can enter into the hydrophobic inner cavity of beta-CD and shows an obvious oxidation peak on the P beta-CD/EG modified glassy carbon electrode. In the presence of BPA, the RhB molecules are displaced by BPA because the host-guest interaction between beta-CD and BPA is stronger than that between beta-CD and RhB. As a result, the oxidation peak current of RhB (I-RhB) decreases and the oxidation peak current of BPA (I-BpA) increases correspondingly. The logarithmic value of I-BPA/I-RhB is linear with the logarithm of BPA concentration in the range of 1-6000 nM and the detection limit is 52 pM (S/N = 3). This strategy provides a new approach for sensitive detection of BPA, and has promising applications in the detection of organic pollutants in real environmental samples. (C) 2015 Elsevier B.V. All rights reserved.