Including the rare cubane cluster cobalt coordination polymer as the fluorescent sensing material for selectively and...

More and more attention has been paid to food safety. Due to the overuse and misuse of antibiotics, the problem of antibiotic residues in animal food is one of the important challenges to ensure food safety. The development of a feasible strategy to detect antibiotic residues in animal food has become desirable. In this paper, we creatively synthesize a water-stable fluorescence sensing material, namely, Co(Ⅱ)-Coordination polymer [Co₂(CA) (L)_0.5 (H₂O)₃] _n (L = 1,4-bis(imidazole-1-ylmethyl) benzene, CA= Citric acid). The single crystal X-ray diffraction shows that it crystallizes in tetragonal space group I-4. It is worth mentioning that there exists the rare Co₄(μ₃-O)₄ cubane cluster structure and Co₈ cluster units. Those adjacent Co₈ cluster units are connected into an infinite two-dimensional net structure by four flexible bridged L ligands. Finally, the Co(Ⅱ)-Coordination polymer (CP) further develops into the three-dimensional supramolecular structure via the hydrogen bonds of O-H⋯O and C-H⋯O. It could selectively detect the antibiotic-nitrofurantoin (NFT) residue by way of fluorescence quenching, Co-CP for the detection of NFT shows broad linearity from 0 to 200 μM, with a detection limit of 0.13 μM and strong anti-interference ability. It is used to detect the NFT residual of tap water and milk with a spiked recovery of 86.35-112.47 %.