Molecularly imprinted polymers-coated gold nanoclusters for fluorescent detection of bisphenol A

Abstract

A flexible fluorescent sensing strategy for the recognition and detection of bisphenol A (BPA) has been proposed based on molecularly imprinted polymers (MIPs)-coated gold nanoclusters (AuNCs), by taking advantages of the high selectivity of MIPs and the strong fluorescence property of AuNCs. SiO2@AuNCs were initially prepared by making use of the powerful amido bonds between carboxyl-terminated AuNCs and amino-functionalized SiO2 nanoparticles. Then MIPs-coated AuNCs were formed by anchoring MIP layer on the surface of SiO2@AuNCs via a sol–gel process. In the presence of imprinting template BPA, a Meisenheimer complex could be formed between BPA and the primary amino groups on the surface of the AuNCs, and the photoluminescent energy of AuNCs would be transferred to the complex, and thereby result in the fluorescence quenching of AuNCs. The fluorescence-quenching fractions of the sensor presented a satisfactory linearity with BPA concentrations over the range of 0–13.1μM and the detection limit could reach 0.10μM. Distinguished selectivity was also exhibited to BPA over other possibly competing molecules. Moreover, the sensor was successfully applied to determine BPA in seawater, and the average recoveries of BPA at three spiking levels ranged from 91.3 to 96.2% with relative standard deviations below 4.8%. This AuNCs-MIPs based sensor provided great potentials for recognition and determination of phenolic environmental estrogens in complicated samples.