A molecularly imprinted fluorescence sensor for sensitive detection of tetracycline using nitrogen-doped carbon dots-embedded zinc-based metal-organic frameworks as signal-amplifying tags

Tetracycline (TC) residues not only endanger human health, but also are detrimental to the sustainable development of aquaculture and animal husbandry. Herein, a novel fluorescence sensor with high sensitivity and selectivity was developed based on nitrogen-doped carbon dots embedded in zinc-based metal-organic frameworks and incorporating molecularly imprinted polymer (ZIF-8&N-CDs@MIP). The physical and chemical properties of the ZIF-8&N-CDs@MIP had been characterized by SEM, TEM, FTIR, XRD, BET, TGA, etc. Under optimal conditions, the limit of detection (LOD) of the novel sensor was 0.045 μg mL-1 with the concentration of TC in the range of 0.1-4.0 μg mL-1. In addition, the prepared imprinted polymers showed superior adsorption selectivity to tetracycline compared with non-imprinted polymers, and the quenching mechanism of ZIF-8&N-CDs@MIP was demonstrated to be attributed to the inner filter effect (IFE). This work provided an effective and reliable method for the specific detection of tetracycline and was successfully applied in milk and egg samples with satisfactory recoveries (80.67-95.22%).