Application Research Of Metal Organic Framework And Its Derivatives In Luminol Chemiluminescence System

Chemiluminescence analysis is widely used in analytical detection because of its low detection limit,rapid analysis,wide linear range and simple device.As one of the classic chemiluminescent reagents,Luminol exhibited good water solubility and high luminescence quantum yield.However,luminol produces weak chemiluminescence in the presence of H₂O₂.Thus,it is necessary to introduce a catalyst in the luminol-H₂O₂ CL system to improve the sensitivity of the analytical detection.In recent years,many researches on nanomaterials with high performance activity as catalysts have been reported,including metal nanoparticles,metal oxide nanoparticles,and carbon materials.On the basis,we successfully synthesizes a series of nanomaterials with excellent chemiluminescence activity by optimizing the preparation method since metal-organic framework possess high specific surface area,adjustable pore size and rich active sites,etc.The luminol-H₂O₂ CL system,a model reaction,was used to explore the relationship between different preparation conditions,the structure and catalytic properties of the obtained materials.Further,the proposed sensor were successfully used for highly sensitive detection of glucose in biological samples.The research work is divided into the following aspects:Chapter 1:Literature review.A series of nanomaterials with good catalytical properties used in luminol-based chemiluminescence are summarized.Chapter 2:In this chapter,we adopts the strategy of surface modification.Firstly,MOF-235 is synthesized by solvothermal method,and then?-cyclodextrin??-CD? is successfully modified on the surface of MOF-235 due to the coordination between Fe³⁺ in MOF-235 and-OH in ?-CD.The obtained MOF-235/?-CD complex showed good water dispersibility.The morphology and structure of the composites were analyzed by XRD,TGA,FTIR and SEM,which certified that the MOF-235/?-CD complex was successfully prepared.Under alkaline conditions,MOF-235/?-CD greatly catalyzed the reaction of luminol-H₂O₂ to produce enhanced chemiluminescence,which was 30 times stronger than the luminol-H₂O₂ reaction.The analysis of chemiluminescence kinetics,chemiluminescence spectroscopy and free radical trapping experiments demonstrated that MOF-235/?-CD was an effective catalyst that catalyzed the oxidation of luminol to produce enhanced chemiluminescence,which may attributed that the synergistic effect of the active site in MOF-235 and?-CD promoted the production of a large number of reactive oxygen species such as hydroxyl radicals?·OH? and superoxide radicals(O₂^·-).Because glucose oxidase catalyze glucose to produce hydrogen peroxide,a rapid,highly sensitive and highly selective method for the detection of glucose was constructed.The proposed sensing strategy coupled with CL detection method showed low detection limits of 5 nM and 10 nM for H₂O₂ and glucose,respectively.Successful application of the MOF-235/?-CD hybrid in CL assay of glucose in real human serum samples is demonstrated as an efficient catalyst for sensitive chemiluminescence analyses.The success of this work favors to facilitate the future development in CL catalysts via MOF functionalization.Chapter 3:In this chapter,we adopted the two-step strategy of carbonization in two different atmospheres.The as-prepared precursor ZIF-67 is firstly carbonized at 600? in N₂ to obtain Co nanoparticles uniformly dispersed in the nitrogen-rich carbon polyhedron.And then the obtained Co nanoparticles was further carbonized in the air at 200 ? to make Co nanoparticles partially oxidized to Co₃O₄ nanoparticles,resulting in a core-shell structured Co@Co₃O₄/NC polyhedrons.The complexes have highly chemiluminescence activity,and the significantly enhanced chemiluminescence generated that the complexes catalyze the reaction between luminol and peroxide,which is about 80 times that of luminol-H₂O₂.Thence,the luminol-H₂O₂ CL reaction was used as a model system,and the mechanism of its function was explored by flow injection chemiluminescence analysis.By its chemiluminescence kinetics,chemiluminescence spectroscopy and free radical trapping experiments,its highly efficient chemiluminescence activity may be due to the uniform dispersion of core-shell structure of Co@Co₃O₄ in the N-doped carbon matrix.The complexes with unique structure accelerated the transfer of electrons and promoted the decomposition of hydrogen peroxide,which produced abundant hydroxyl radicals?·OH? and superoxide radicals(O₂^·-).Based on the good catalytic effect of Co@Co₃O₄/NC complexes on luminol-H₂O₂ reaction,we constructed a rapid and sensitive method for the detection of H₂O₂ and glucose.Under the optimal experimental conditions,the proposed method possesed the linear range of H₂O₂ from 5 nM-2?M,the detection limit?LOD,3?? is as low as 2 nM,and the linear range of glucose detection is 8 nM-1?M,the LOD of glucose?3?? is 4 nM.Further,the method is applied to the determination of glucose in human serum samples,and the results are reliable.Chapter 4:The as-prepared hollow ZIF-67 was carbonized in air at 400? to obtain a hollow Co₃O₄/C polyhedrons,and then reacted with FeSO₄ to self-assemble FeOOH nanorods on the composite.The obtained Co₃O₄/FeOOH uniformly dispersed on an carbon substrate?denoted Co₃O₄/FeOOH/C?.The complexes exhibiting good catalytical activity can catalyze the reaction of hydroxide peroxide and luminol to produce significantly enhanced chemiluminescence.In particular,the possible catalytic mechanism was explored by CL spectroscopy,CL kinetics experiments and free radical trap experiments.Based on the good chemiluminescence performance of Co₃O₄/FeOOH/C complexes,a rapid and highly sensitive method for the determination of glucose was established.Under the optimal experimental conditions,the analytical method detects the linear range of glucose from 5 nM-2?M,and the detection limit?LOD,3?? is as low as 5 nM,which is successfully applied to the determination of glucose in human serum.