Construction Of Transition Metal Organic Framework Sensor And Fluorescence Recognition Of Nitro Antibiotics

Antibiotics are widely used in medical and health care and agricultural breeding,and play an important role in the treatment of infectious diseases to save the lives of patients,the prevention and control of animal epidemics,the improvement of breeding efficiency,and the protection of public health safety.At the same time,the frequent use of antibiotics leads to antibiotic residues with certain biological activity,which are discharged into the environment through domestic sewage,medical wastewater,animal feed and livestock and poultry breeding wastewater,and can be enriched in the human body in different ways,which are serious harm to human health and environmental safety.Therefore,the detection of antibiotics in different environmental media is particularly urgent.Compared with traditional detection techniques and means,fluorescence sensing technology has the advantages of low detection cost,high sensitivity,fast reaction,and good selectivity,which has attracted widespread attention.Transition Metal-Organic Frameworks（MOFs）with high specific surface area,the structure can be cut,easy to function and good quantity,good quantum yield and fluorescence characteristics of life,as a potential fluorescence sensors and quantitative detection of materials,in a simple,sensitive and rapid detection and monitoring of environmental pollutants antibiotics showed great prospect.Based on above,this thesis synthesized three kinds of fluorescent MOFs sensors that can specifically identify nitroimidazoles and nitrofurans antibiotics in water.The main research contents and achievements are as follows:1.Three novel transition metal MOFs single crystals were synthesized by solvothermal method.MOF 1 is{[Cd₂L₁（DMF）₂·H₂O]·2DMF}_n,MOF 2 is[Zn₂L₁·H₂O]_n,andMOF3is[Cd₂L₂（DMF）₂·H₂O]_n,where L₁=2,5-bis（（4-carboxyphenyl）amino）terephthalicacidand L₂=2,5-bis（（3-carboxyphenyl）amino）terephthalic acid.2.The crystal structures of MOF 1-3 were determined by X-ray single crystal diffraction,and were characterized by infrared,thermogravimetric,PXRD and elemental analysis.Structural analysis shows that MOF 1 and 3 have two-dimensional spatial structure,while MOF 2 presents a three-dimensional structure.The results of PXRD and thermogravimetric analysis showed that MOF 1-3 had higher phase purity and thermal stability.3.The detection ability of MOF 1 and 2 to nitroimidazoles in water was analyzed by fluorescence spectroscopy.The results showed that MOF 1 and 2 could specifically identify nitroimidazole antibiotics,and had the characteristics of short response time,excellent repeatability and strong fluorescence stability.However,the detection limit of MOF 1 is lower than that of MOF 2.The fluorescence quenching mechanism study showed that the fluorescence quenching effect of MOF 1 was attributed to the combination of photo-induced electron transfer and energy-competitive absorption,and the fluorescence response mechanism of MOF 2 belonged to photo-induced electron transfer.4.The detection performance of MOF 3 for nitrofuran antibiotics in water was explored by using a fluorescence spectrometer.The experimental results show that MOF 3 can quickly identify nitrofuran antibiotics in water,with low detection limit and strong anti-interference ability,reusable,fast response,excellent water stability and p H stability,which could achieve sensitive detection of nitrofuran antibiotics in water.The fluorescence quenching mechanism study revealed that the fluorescence quenching effect of MOF 3 was attributed to the combination of light-induced electron transfer and energy-competitive absorption.