摘要

Bisphenol A (BPA) is an endocrine disrupting chemical, which can mimic estrogen and bring about a series of negative impact on human health. Herein, we developed a novel dual-signal sensor by coupling nanoporous gold leaf (NPGL) with thiolated beta-cyclodextrin (SH-beta-CD) to realize sensitive and selective determination of BPA. Modification with NPGL and self-assembling of SH-beta-CD on gold electrode were tracked by scanning electron microscopy, energy-dispersive spectroscopy and electrochemical measurements. The dual signaling method is based on the competitive host-guest interaction by recording the signals from both target molecule BPA and probe molecule methylene blue (MB). Due to the different binding ability of host molecule (beta-CD) towards BPA and MB, BPA is able to enter beta-CD cavities and replace the pre-existing MB, resulting in the decreased oxidation peak current of MB and the increased oxidation peak current of BPA. The summation of both current changes (vertical bar Delta I-MB vertical bar + Delta I-BPA) is linearly dependent on Napierian logarithm of BPA concentration from 3 x 10(-7) M to 1 x 10(-4) M with a detection limit of 6 x 10(-8) M(S/N = 3). It is noted that the detection limit obtained by dual-signaling is much lower than that using single Delta I-BPA as the response signal. This newly developed sensor was further adopted to measure BPA in milk and tap water. The proposed dual-signal strategy and the established hybrid electrochemical sensor have great potential applications in biomarker detection, food safety testing and environmental monitoring.