A sensitive and selective fluorescence sensing of bisphenol A based on magnetic Fe3O4@SiO2@QDs@MIPs nanoparticles

A flexible magnetic and fluorescent sensing for the recognition and detection of bisphenol A (BPA) based on a hybrid magnetic Fe3O4@silica nanoparticle@Mn:ZnSquantum dots@molecularly imprinted polymers nanoparticles (Fe3O4@SiO2@QDs@MIPs NPs) was designed. Because of the high selectivity of MIPs, the strong fluorescence property of Mn:ZnS QDs, the nice magnetism of Fe3O4 and good water solubility of SiO2, the Fe3O4@SiO2@QDs@MIPs NPs could detect BPA effectively in human urine. In the presence of BPA, a new compound was produced via the amino group of Fe3O4@SiO2@QDs@MIPs NPs and the hydroxyl group of BPA, the energy of the QDs would be transferred to the compound, which led to fluorescence quenching. The relative fluorescence intensity decreased linearly with the increasing of BPA concentration in the range of 50 to 700 ng/mL, the detection limit was 1.6 ng/mL. In addition, the sensor has a strongly selectivity with an imprinting factor of 8.7, distinguished selectivity was also exhibited to BPA over other possibly competing molecules. On the basis of the merits of the Fe3O4@SiO2@QDs@MIPs NPs, the sensor could be applied to detect BPA in human urine sample successfully