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:ZnS quantum dots@molecularly imprinted polymers nanoparticles (Fe3O4@SiO2@QDs@MIPs NPs) has been designed. Because of the high selectivity of MIPs, the strong fluorescence property of Mn:ZnS QDs, good magnetism of Fe3O4 and good water solubility of SiO2, the Fe3O4@SiO2@QDs@MIPs NPs can effectively detect BPA effectively in human urine. In the presence of BPA, a new compound is produced via the amino group of Fe3O4@SiO2@QD5@MIPs NPs and the hydroxyl group of BPA, the energy of the QDs is transferred to the compound, which led to fluorescence quenching. The relative fluorescence intensity has decreased linearly with the increasing of BPA concentration in the range 50 to 700 ng/mL and the detection limit is found to be 1.6 ng/mL. In addition, the sensor has shown a strong selectivity with an imprinting factor of 8.7 and distinguished selectivity is also exhibited to BPA over other possibly competing molecules. On the basis of the merits of the Fe3O4@SiO2@QDs@MIPs NPs, the sensor can be applied to detect BPA in human urine sample successfully.