A reversible fluorescence sensor based on insoluble β-cyclodextrin polymer for direct determination of bisphenol A (BPA)

Based on the reversible recognizing reaction between insoluble β-cyclodextrin polymer (β-CDP) and bisphenol A (BPA), a bifurcated optical fiber chemical sensor has been proposed for continuous monitoring of BPA. When immobilized in a plasticized poly(vinyl chloride) membrane of 5 μm thickness, β-CDP extracts BPA from aqueous solutions into the bulk membrane phase and reacts with the analyte to form an inclusion complex with high fluorescence efficiency. Formation of the complex gives a significant enhancement of the intrinsic fluorescence (λex/λem = 286 nm/312 nm) of BPA which is suitable for signaling the occurrence of the host–guest recognizing interaction. The fluorescence sensor exhibits a dynamic detection range from 6.0 × 10−6 mol/L to 1.0 × 10−3 mol/Lwith a detection limit of 1.0 × 10−6 mol/L. The high selectivity of the sensor toward BPA depends on the synergistic shielding effect by β-CD units and an optimal space-matching between the host and the guest. The proposed sensor was successfully used for the determination of BPA in water samples.