MIP-coated Eu(BTC) for the fluorometric determination of lincomycin in eggs

Lincomycin (LCM) has low ultraviolet (UV) absorption and thus, its determination requires complex instrumentation. Herein, a novel fluorometric probe based on an europium metal–organic framework coated with molecularly imprinted polymers (Eu(BTC)-MIP) was fabricated for the selective determination of LCM. First, highly luminescent Eu(BTC) was synthesized at room temperature. Then, through a simple co-polymerization process, MIPs were formed on the Eu(BTC) surface in the presence of LCM as template molecules to obtain Eu(BTC)-MIP. Eu(BTC) acted as a supporting substrate and antenna, and the MIP layer provided specific binding sites for LCM. Due to the advantages of both Eu(BTC) and MIPs, the probe had a long emission lifetime, strong fluorescence and specific recognition. Under the optimized conditions, the probe achieved the selective determination of LCM in the concentration range of 10 to 100 μg L−1 with a detection limit (LOD) of 7.18 μg L−1 (S/N = 3). This method is attractive because of its low cost, good selectivity, ready availability and simple manipulation without the need for complex instrumentation. Furthermore, the probe was successfully employed to detect LCM in egg samples with a recovery in the range of 88.02% to 97.29% and a relative standard deviation (RSD) of less than 3.46%. The satisfactory results demonstrate that the proposed probe based on Eu(BTC)-MIP can be used for the quantitative analysis of LCM and exhibits great potential for LCM determination in food samples. Also this study provides a new perspective for the determination of weak ultraviolet absorption or non-fluorescent substances without conjugated groups.