In this study, magnetic fluorescence molecularly imprinted polymers were fabricated and used for the selective separation and fluorescence sensing of trace bisphenol A (BPA) in environmental water samples. The carboxyl-functionalized FeO_x magnetic nanoparticles were conjugated with mercaptoethylamine-capped Mn²⁺ doped ZnS quantum dots to prepare magnetic FeO_x and ZnS quantum dot nanoparticles (FeO_x/ZnS NPs). Additionally, molecular imprinting on the FeO_x/ZnS NPs was employed to synthesize core-shell molecularly imprinted polymers. The resulting nanoparticles were well characterized using transmission electron microscopy, Fourier transform infrared spectra, vibrating sample magnetometer and fluorescence spectra, and the adsorption behavior was investigated. Binding experiments showed that the molecularly imprinted FeO_X/ZnS NPs (FeO_x/ZnS@MIPs) exhibited rapid fluorescent and magnetic responses, and high selectivity and sensitivity for the detection of bisphenol A (BPA). The maximum adsorption capacity of FeO_x/ZnS@MIPs was 50.92 mg·g⁻¹ with an imprinting factor of 11.19. Under optimal conditions, the constructed fluorescence magnetic molecularly imprinted polymers presented good linearity from 0 to 80 ng mL⁻¹ with a detection limit of 0.3626 ng mL⁻¹ for BPA. Moreover, the proposed fluorescence magnetic polymers were successfully applied to on-site magnetic separation and real-time fluorescence analysis of target molecule in real samples.

A new strategy is proposed for construction of multifunctional nanocomposites which possess unique optics, electricity, and magnetism. The mercaptoethylamine (MEA) was capped on the surface of Mn²⁺ doped ZnS quantum dots (ZnS:Mn²⁺ QDs@MEA), and carboxyl group functionalized Fe₃O₄ magnetic nanoparticles (Fe₃O₄@COOH) were synthesized through a solvo-thermal method in one step. The Fe₃O₄@COOH was conjugated with ZnS:Mn²⁺ QDs@MEA to synthesis magnetic and fluorescent Fe₃O₄/ZnS nanocomposites (Fe₃O₄/ZnS NCs) through a facile 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) processes. The morphology and structure of as-prepared Fe₃O₄/ZnS NCs were characterized by transmission electronic microscopy (TEM), fluorescence spectrum, and vibrating sample magnetometer (VSM). Binding experiments were carried out to evaluate the binding performance of Fe₃ O₄/ZnS NCs. The maximum adsorption capacity of Fe₃O₄/ZnS NCs for lysozyme was 234.74 mg · g^–1. The formed multifunctional nanoparticles integrate the optical and magnetic properties together, which provides a potential application in the field of bioseparation and biodetection.