SiO₂-coated molecularly imprinted sensor based on Si quantum dots for selective detection of catechol in river water

Selectivity is an important goal to the final analysis of targets. But for silicon quantum dots (Si QDs), a kind of QDs with low-toxic from a wide range of sources, the selective detection is mainly through the special force between Si QDs and targets. Yet it is necessary to find a way to realize the selective detection for more common target analysis. Herein, the molecularly imprinted polymers based on Si QDs (Si QDs@SiO₂ @MIPs) was successfully prepared for selective detection of catechol (CT). Si QDs were firstly modified with 3-Aminopropyltriethoxysilane (APTES), the template molecule CT was effectively contacted with Si QDs after modifications, under the action of cross-linking agent tetraethyl orthosilicate (TEOS), Si QDs@SiO₂ @MIPs were synthesized through the sol-gel method. Si QDs@SiO₂ @MIPs displayed a strong fluorescent emission at 447 nm and were quenched in the presence of CT via dynamic quenching. Under optimum conditions, the relative fluorescent intensity of Si QDs@SiO₂ @MIPs was gradually weakened in response to the increased CT concentrations in the range of 0.018–100 µM. A low detection limit of 0.018 µM for CT determination was obtained. This developed strategy was evaluated by detecting CT in the real river water samples. Satisfactory recoveries were obtained in the range of 97.77−101.70%. Moreover, the high-performance liquid chromatography (HPLC) method was conducted as a reference of CT detection, the results powerfully demonstrated the accuracy and feasibility of the method proposed in this work. Thus, the strategy is possibly a promising method for Si QDs to expand more target detection.