The Design Of Functionalized Zirconium Metal-Organic Frameworks Fluorescent Probe And Study Of Small Molecule Sensing Performance

With the development of global industrialization and urbanization,more and more attention has been paid to environmental pollution.As one of the most relevant environmental pollutants,organic dyes are discharged into lakes,oceans,drinking water,and even enter the human body through the food chain.In addition,physical fitness has been a prerequisite for human survival forever.As an essential microelement for human beings,iodine is closely related to the growth and development of human body and metabolism.Excessive or lack of iodine intake will have serious impact on health.Glucose is also an indispensable substance in human body.It is not only one of the main sources of energy,but also participates in the metabolic process of human body.The disorder of glucose metabolism can cause many diseases,such as diabetes,cardiovascular disease,alzheimer’s disease and so on.Therefore,finding a simple,rapid and highly sensitive method to detect dye contaminants and small molecules of iodine and glucose has become an important problem we are facing at present.Therefore,two functionalized zirconium-based metal-organic frameworks fluorescent probes were designed and constructed successfully in this paper,and highly sensitive fluorescence analysis methods were established for the detection of dye contaminants,iodine and glucose.The main research contents of this paper are as follows:（1）The zirconium metal-organic framework material MOF-808 was synthesized by a simple hydrothermal method,and the lanthanide luminescence material Eu³⁺@MOF-808 fluorescent probe was successfully prepared by the post-synthesis modification method.Eu³⁺@MOF-808 exhibits sharp characteristic emission peaks of Eu³⁺at 579,592,616,651 and 699 nm at the excitation wavelength of 285 nm,and its excellent luminescence performance and good fluorescence stability contribute to its outstanding sensing and detection ability.Through the fluorescence response to four dyes,combined with the spectral overlap and energy transfer relationship,the fluorescence quenching effect based on the mechanism of fluorescence resonance energy transfer（FRET）of BG,MG and IDR and the inner filter effect（IFE）of ARS was proved.A method for the fluorescence detection and analysis of four common dyes,malachite green（MG）,bright green（BG）,alizarin red S（ARS）and indigo red（IDR）was established.The p H and reaction time were optimized.Under the best conditions,the fluorescence probe was used to detect four dyes,it received wide linear ranges（BG:0.125-45μM,IDR:2-150μM,MG:2-100μM,ARS:2-100μM）and low detection limits（BG:32 n M,IDR:58 n M,MG:77 n M,ARS:133 n M）,the highly sensitive detection of the four dyes was successfully implemented.The interference experiments show that the probe has good selectivity and anti-interference ability.In addition,a portable detection reagent bottle has been developed,which can be used for visual on-site monitoring of dye samples under UV light.The probe has been successfully applied to the detection of IDR in printing wastewater and MG in fish pond water,and satisfactory results have been obtained,which provides a new application platform for water quality monitoring.（2）A dual-emitting RhB-CDs@MOF-808 ratiometric fluorescent probe was successfully constructed by introducing carbon dots（CDs）and rhodamine B（RhB）into the nanocages of MOF-808 by post synthetic modifiction.The constructed ratiometric probe presents the emission at 450 nm of CDs was served as a reference to calibrate the emission at 575 nm attributed to RhB to achieve a remarkable self-calibration function,it overcomes the interference of the fluctuating environmental conditions of the instrument and the concentration of the probe,improves the sensitivity and reliability of the trace analyte,and shows good fluorescence stability.The fluorescence of probe is quenched by I₃^-by virtue of inner filter effect（IFE）and ion association,and the I₃^-is reduced by glucose to achieve the recovery of fluorescence.Based on the fluorescence“quenching”and“recovery”response of RhB-CDs@MOF-808 to I₃^-and glucose,an analytical method of sensing detection was established,which was used as a fluorescent“off”and“on”ratiometric probe.The p H of solution,reaction time and I₃^-ion concentration were optimized.The probe was used for the ratiometric fluorescence detection of I₃^-ions,and RhB-CDs@MOF-808-I₃^-was used as the matrix for the fluorescence recovery detection of glucose.Wide linear ranges（I₃^-:0-220mM,glucose:0-180mM）and low detection limits（I₃^-:0.031mM,glucose:0.026mM）were obtained.The interference experiments show that the probe has good selectivity and anti-interference ability in the detection of I₃^-and glucose.And the probe has been successfully exploited to the determination of I₃^-and glucose in real samples of food and biology.A molecular logic gate was established to enrich the applied fields of ratiometric fluorescence probe.The prepared RhB-CDs@MOF-808 probe can realize the accurate,continuous,specific and highly sensitive detection of I₃^-and glucose,which can provide a new approach for the development of low-cost and sensitive biological and clinical diagnostic applications.