Fluorometric detection of bisphenol A using β-cyclodextrin-functionalized ZnO QDs

The estrogenic property of bisphenol A (BPA) leads to potential adverse health and ecological effects. A simple, selective, and cost-effective sensor capable of detecting BPA would have a noteworthy relevance for the environmental system. The present work illustrates the synthesis and characterization of β-cyclodextrin (β-CD) functionalized zinc oxide (ZnO) quantum dots (QDs) for the selective detection of BPA. BPA has a fluorescence quenching effect on functionalized ZnO QDs, and the decrease in fluorescence intensity is associated with the BPA concentration between 2 and 10 μM. Under the optimum reaction condition, a good linear correlation was obtained between relative fluorescence-quenching intensity of β-cyclodextrin-functionalized ZnO QDs and BPA concentration (R² = 0.9891). The lower detection limit of functionalized QDs for BPA was estimated to be 0.19 μM, which is lower than the toxic limits in aquatic biota. The fluorescence-based detection of BPA may be ascribed to the electron transfer mechanism, which is elucidated with scientific details from the literature.