Synthesis Of Metal-organic Framework Encapsulated Dye And Enzyme Composites For Sensing

Metal-organic framework?MOF?is a new generation of crystalline porous material,which is characterized by simple synthesis conditions,diverse structures and easily modified pore surfaces.However,most MOFs possess low mechanical strength and poor chemical stability,which limit their development and application.In recent years,related composite materials based on MOF and other functional materials have been widely developed.Compared with single materials,MOF-based composite materials possess larger specific surface area and porosity,better stability and catalytic performance,etc.It makes up for the limitations of any single material in the application,while introducing new features and functions.Based on the relative advantages of MOF-based composite materials,the thesis has realized its applications in ratiometric fluorescence detection of fluoride ions and trace water in organic solvents,and portable glucose meters for hydrogen sulfide detection.The relevant research content is as follows:1.Rhodamine 6G encapsulated into Uio-66-NH₂ for selective ratiometric fluorescence detection of fluoride ions.The R6G@Uio-66-NH₂ composite was synthesized by in-situ encapsulation of rhodamine 6G?R6G?in a zirconium-based metal organic framework?Uio-66-NH₂?by a simple hydrothermal method.The composite material can produce double emission under single excitation.In the presence of fluoride ion,the fluorescence emission intensity appears due to the hydrogen bonding between2-aminoterephthalic acid and fluoride ion in Uio-66-NH₂.The fluorescence emission intensity increased and remained unchanged.Therefore,it can be used as a ratiometric fluorescence sensor to achieve fast and sensitive detection of fluoride ions.The detection limit is as low as 47 nM,and found that the material has higher sensitivity and better reproducibility for the detection of fluoride ion in aqueous solution,which proves the practicability of the sensor in actual samples.2.Rhodamine 6G encapsulated into Eu-MOF for distinguishing between aprotic/protonic polar solvents and ratiometric fluorescence detection of water in organic solvents.Developing a convenient and rapid detection method for water is greatly desirable in the fields of chemistry industry.Herein,we present a simple and effective strategy combining a fluorescence sensor and one-to-two fluorescence colorimetric logic operation to monitor water in a wide range of organic medium and classify aprotic/protic polar solvent.The dual-emitting luminescent detector was prepared by incorporating a fluorescent dye Rhodamine 6G?R6G?with strong green light emission within a red light-emitting Eu-MOF through“bottle around ship”method.R6G@Eu-MOF displays completely different fluorescence response behaviors to various organic solvents.Thus,making use of the intensity ratio of different fluorescence emission centers,a 3D decoded map was proposed to reliably and effectively distinguish different aprotic/protic polar solvent.Moreover,R6G@Eu-MOF exhibited two different ratiometric sensing mode when detecting water in aprotic/protic polar solvent due to hydrogen bonding interaction,that is ratiometry with one reference signal or two reversible signal changes.Furthermore,using water content as the input and two kinds of fluorescence emission as output signals,a one-to-two logic gate system was constructed,making it possible to develop an intelligence system for water detection.Overall,we demonstrated for the first time that R6G@Eu-MOF could serve as an efficient platform for tracing of water in organic medium and distinguishing protic/aporotic polar organic solvents.3.Glucoamylase encapsulated into Cu/Zn-ZIFs for detection of H₂S with portable blood glucose meter.Studies on the use of portable blood glucose meters to detect non-glucose targets have been reported,but no MOF-based composite materials have been used for this purpose.The work mainly used the normal temperature stirring method to rapidly synthesize Cu/Zn-ZIFs-coated glucoamylase??-amylase?composites??-amylase@Cu/Zn-ZIFs?.In the presence of H₂S,due to S^2-and Cu²⁺can form CuS,which partially disintegrates Cu/Zn-ZIFs.After the release of?-amylase,starch can be hydrolyzed to glucose,and the amount of H₂S can be determined indirectly by measuring the amount of glucose with a blood glucose meter.The detection limit is as low as 9.3 nM.The method enables fast,convenient and real-time detection of H₂S.