Preparation Of Fluorescent Probes And Nanozymes Based On Metal-organic Frameworks And Their Preliminary Analytical Application

Metal-organic frameworks composite functional materials possess the performance advantage of synergistic action from two or more components.Especially,gold,silver,copper,and other precious metal-organic frameworks(MOFs)have extensive applications in the field of sensing analysis.In this study,an amino-derived zinc-based MOFs fluorescent probe and a copper-gold composite MOFs nanoenzyme catalytic material were prepared.Combined with the construction of a superwetting microdots array detection platform,two simple,rapid,and sensitive detection techniques have been developed to efficiently analyze copper and iron ions in red wine and herbicide glyphosate in cabbage juice.Specific research contents include:(1)Amino-derived zinc-based MOFs(Zn-MOFs)have been prepared using the solvothermal method and fixed as fluorescent probes in superwetting microdots array.A high-throughput fluorescence assay method was developed for the highly sensitive detection of copper and iron ions in red wine samples(Chapter 2).The superwetting microdots array was prepared using hydrophobic long-chain silane and polyacrylic acid on glass slides.The amino-derived surface was then created using aminopropyl triethoxysilane in the microdots array to bond and immobilize the amino-derived Zn-MOFs probe,resulting in the superwetting microdots array based on the Zn-MOFs probe.It was found that the fluorescence quenching of the Zn-MOFs probe could be selectively induced by the addition of copper and iron ions.Consequently,a fluorescence detection platform for copper and iron ions based on the microdots array was established.The results demonstrated that the method could simultaneously detect copper and iron ions could be quantified in the concentration range of 0.010-25 μM and the limit of detection of 0.035 μM.Specifically,the selective analysis of iron ions could be achieved by adding a certain amount of histidine complexing masked copper ions,with a detection range of0.10-100.0 μM and the limit of detection of 0.025 μM.Moreover,the developed fluorescence detection platform can enable the accumulation of targeting ions in complicated samples.Also,the cross-contamination of different liquid droplets of samples can be avoided.(2)A Cu-Au-MOFs catalytic functional material has been prepared to develop a colorimetric method for determining glyphosate residues in cabbage(Chapter 3).Cu-Au-MOFs composites were prepared using a one-pot solvothermal method.It was discovered that the peroxidase activity of Cu-Au-MOFs increased more than threefold compared to that of Cu-MOFs,indicating that doping of gold in Cu-MOFs significantly enhanced the catalytic activity.However,once the herbicide glyphosate was added,the catalytic activity of Cu-Au-MOFs composites decreased rapidly.Therefore,a highly sensitive colorimetric analysis method based on Cu-Au-MOFs catalysis was established.The linear range of glyphosate detection was 0.5-6.0 ng/ml,and the limit of detection 0.50 ng/ml.Furthermore,the linear range of glyphosate residues in cabbage was 0-10.0 ng/ml and the limit of detection 0.8 ng/ml.