Water-stable Ag (Ⅰ) coordination polymer sensors to selectively and sensitively detect the chlortetracycline via fluorescence red-shift and turn-on effect.

The antibiotic residue resulting from the abuse and overuse of antibiotics has threatened food safety and the environment. Establishing new detection strategies for antibiotic residues in food and the environment is necessary. A "turn-on" fluorescence sensor-[Ag(BIX)]n⋅ n(HBA) (Ag-CP)(BIX = 1,4-bis(imidazole-1-ylmethyl) benzene, BA = benzoic acid) was constructed herein using a convenient one-pot strategy. The ample benzene ring, imidazole ring, and free BA of Ag-CP provide the specific interaction sites for the interaction between the fluorescence sensor and the target. Due to its excellent chemical and fluorescent properties, it has been used to detect Chlortetracycline (CTC) sensitively. To our knowledge, Ag coordination polymer has not been previously reported for the detection of CTC. It is worth mentioning that the fluorescent intensity of Ag-CP remarkably enhances and the wavelength of the emission peak is red-shifted under the synergistic effect between the CTC and Ag-CP. Selectivity and sensitivity for detecting the CTC have been achieved over the concentration from 0.05 μM to 100 μM, along with the good linear fitting (R2 ≥ 0.9690) and the low limit of detection (34 nm). The recovery percentage in spiked food samples was assessed to be 84.12-96.82 %, and the RSD is less than 4.75 %. These results manifested that the Ag-CP-based fluorescence sensor, validated by the HPLC, represented good sensitivity and high precision. Therefore, our work reveals the advantages of coordination polymer-based fluorescence sensors and puts forward a novel strategy for the detection of antibiotic residues in food safety.