Construction of a Cd(II)-Based Metal-Organic Framework for Selective Luminescent Sensing of Chloramphenicol in Milk and Honey Samples

A new and water-stable metal-organic framework, [Cd2(L)2(tmd)]& BULL;3H2O (MOF 1), was successfully synthesized by mixed ligands of H2L and tmd under solvothermal condition (H2L= 5-acetamidoisophthalic acid, tmd= 4,4-trimethylenedipyridine). Single-crystal X-ray diffraction shows that the structural unit of MOF 1 is a tetranuclear [Cd4(L)6] primary building unit. Fluorescence sensing experiments revealed that MOF 1 exhibited selectivity and sensitivity detection of Chloramphenicol (CHL) antibiotic in aqueous solutions. The fluorescence quenching effect showed that MOF 1 had a very low detection limit for CHL (LOD= 0.11 & mu;M). More importantly, MOF 1 can be used as a new fluorescence sensor for the detection of CHL in milk and honey samples with very good re-coveries of 98.2-103.0 % and 97.0-98.9 %, respectively. Furthermore, the internal filtration effect (IFE) and photoelectron electron transfer (PET) may be responsible for the fluorescence quenching efficiency.