Construction And Characteriation Of Novel Cu²⁺ Chemical Sensor Based On Metal-Organic Framework

Chapter 1: The structure,properties and synthetic method of Matal-Organic Frameworks(MOFs)materiasls were briefly introduced and then the applications in analytical chemistry were summarized.Based on the introduction above,the project of introducing guest sensing materials into MOFs materials was put forward based on the introduction above,so that we could achieve the purpose of synthesizing novel MOFs materials for chemical sensing oriented.Chapter 2: The pyridoxal hydrazide(PAH)molecule,MOFs materials of ZIF-8 and the composites of PAH/ZIF-8 were prepared gradually and characterized by 1HNMR,13 CNMR,FTIR,XRD,SEM and BET.It indicated that the optimal reaction conditions for PAH and ZIF-8 were 48 h,40 ? and p H = 7.0 after investigating the reaction system.The average diameter of the spherical composites was 82 nm,and the PAH and ZIF-8 in PAH/ZIF-8 composites were combined by hydrogen bonds and ?-? stacking rather than simple mechanical mixing.The as-prepared PAH/ZIF-8 composites had fluorescence emission at 473 nm under the excitation of 354 nm.The mass fraction of PAH in the composites was about 20 % estimated by the thermogravimetric analysis curves and job curve of fluorescence titration.The coordinative complex formation between PAH and Cu2+ could quench the fluorescence intensity of PAH/ZIF-8 composites.In addition,the PAH/ZIF-8 composites had higher sensing efficiency to Cu2+ compared with PAH.All that indicate that the PAH/ZIF-8 will be a potential candidate for Cu2+ sensing.Chapter 3: The practicability of PAH/ZIF-8 composites treated as chemical sensing materials for Cu2+ was investigated.it was found that the optimal value of p H for the interaction of PAH/ZIF-8 composites with Cu2+ was 11.0.The LOD of PAH/ZIF-8 composites to Cu2+ was 1.42 n M calculated by the fluorescent titration curve and the job curve,and the result demostrated that it had higher selectivity to Cu2+ over other ions.Then,the application in real samples and cellular imaging of PAH/ZIF-8 composites were researched,the results shew a satisfactory recovery.Moreover,excellent permeability in cell membrane and low cytotoxicity in cellular imaging of PAH/ZIF-8 composites were illustrated in this thesis.Chapter 4: The salicylaldehyde based rhodamine B hydrazone(RBS)was synthesized by rhodamine B and salicylaldehyde,then the composites of RBS/ZIF-8 was obtained by introducing RBS into ZIF-8.The results of UV-vis absorption spectra,FTIR and X-ray powder diffraction shew that the RBS/ZIF-8 composites were consisted of RBS and ZIF-8,and the small-size RBS do not impact the crystalline integrity of ZIF-8.The mass fraction of the RBS in RBS/ZIF-8 composite was 29.3 % calculated by the thermal analysis curves.The UV-vis absorption intensity of RBS/ZIF-8 composites could be weakened dramatically in the presence of Cu2+ based on the coordinative complex formation between Cu2+ and RBS,the LOD of RBS/ZIF-8 composites to Cu2+ was 0.8 ?M and exhibited highly selectivity to Cu2+ over other ions.Finally,the characteristics and advantages of the host-guest composites consisted of organic sensing molecules and MOFs were summarized briefly and then their development and application in chemical sensing were further envisioned.