Metal-organic framework modified molecularly imprinted polymers-based sensor for fluorescent sensing of tetracycline in milk

Tetracycline (TC) residues have a serious impact on human health, sustainable development of animal husbandry and aquaculture. Herein, a novel sensor (Cr-MOF@MIP) for TC detection was developed by modifying molecularly imprinted polymers (MIPs) on the surface of a luminescent metal-organic framework (MOFs). The sensor not only possesses excellent fluorescence stability and specific recognition sites, but also enables selective aggregation of the target. Subsequently, the physicochemical properties of Cr-MOF@MIP, such as morphological structure, crystal shape, surface area, pore size and functional groups, were characterized. Under the optimized conditions, the relative fluorescence intensity of the Cr-MOF@MIP fluorescent sensor decreased gradually and linearly as the TC concentration increased from 0.2 μg/mL to 50 μg/mL. The limit of detection (LOD) of TC was 0.032 μg/mL. In addition, the sensor has higher selectivity for TC compared to non-imprinted polymers (NIPs), with a bursting mechanism of Cr-MOF@MIP mainly attributed to the fluorescence resonance energy transfer. Remarkably, in the complex systems of milk, its specific detection of TC was demonstrated with satisfactory recoveries (90.06–104.34 %). It is expected that the development of Cr-MOF@MIP sensor will provide a new way of thinking for easy, rapid, highly selective and cost-effective analysis in complex samples.