Highly sensitive fluorescence detection of nitrofurazone and nitrofurantoin in milk and honey using a hydrostable Cd(Ⅱ) metal-organic framework

A new and water-stable Cd (II) metal-organic framework, namely [Cd(mba)(bpdb)0.5] (MOF 1), was successfully designed and synthesized by a mixed ligand of H2mba and bpdb under solvothermal condition (bpdb = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, H2mba = 4-(carboxymethyl)benzoic acid). Single crystal X-ray structural analysis suggests that MOF 1 crystallized in the monoclinic system with the P21/c space group and exhibits a 3D framework based on the infinite [CdO5N] chain. Fluorescence sensing experiments show that MOF 1 can be used as a fluorescence sensor to selectively, sensitively and quickly detect Nitrofurazone (NFZ) and Nitrofurantoin (NFT) antibiotics with very low detection limits of 0.116 μM and 0.123 μM, respectively. More importantly, MOF 1 was able to detect the NFT and NFZ antibiotics in milk and honey samples with good recovery rates. Additionally, the possible fluorescent quenching reasons for NFZ and NFT antibiotics were mainly caused by the fluorescence resonance energy transfer (FRET) and photoelectron electron transfer (PET) mechanism.