Application Of Water-soluble Porphyrin Optical Probe In The Determination Of Acidity And Quantitative Analysis Of Cu²⁺

Porphyrins,a category of macrocyclic compounds origin in nature,in which each atom on the ring is in the same plane with 11 conjugated bonds,giving them a good molecular rigidity.Porphyrin compounds are usually dark in color.Porphyrins play an important role in the metabolism of organisms,for example,chlorophyll is porphyrin compound,while the active centers of biological macro molecules such as myoglobin,catalase and hemoglobin have porphyrin structures.As an aromatic ring,porphyrin is usually simplified as a nearly flat,regular and rigid shape.Although this description is acceptable,and the regular conformation of porphyrin compounds does exist,interactions with proteins may lead to distortions in-plane and out-of-plane in the process of synthesis of porphyrins.Due to their unique characteristics of molecular absorption,the development and application of porphyrin compounds in analytical science is a promising research direction.In recent years,porphyrins exhibit great potential in the area of fluorescence probe,analytical chemistry,photosensitive materials,biochemistry,and dyes.Measurement of pH is important in scientific research,industrial,agricultural,and environmental protection.Most of the pH fluorescent probes have been developed are mainly for neutral and weak acid media.Fluorescent probes working in strong acidity or alkalinity are rarely reported.It is valuable to develop porphyrin optical probes to provide more alternatives in pH detection or sensing.We found that the fluorescence of 5,10,15,20 tetra(4-trimethylamino)phenylporphyrin tetramethylsulfonate(TTMAPP)was quenched strongly by copper ion with excellent specificity in preliminary screening experiments.It shows that TTMAPP has great potential to be a fluorescent probe for copper ion.Thus,the purpose of this paper is to explore the feasibility of TTMAPP as a novel optical probe for the determination of pH and copper ion.In the first chapter,the structure and basic properties of porphyrin compounds are briefly introduced.Secondly,the significance of acidity detection and common detection methods are summarized.The principle,classification and the development of specific fluorescent probe are also described.In the second chapter,based on the "isoemission point" response of TTMAPP to pH,a new method for the determination of pH with tetraphenylporphyrin fluorescent probe was established.In this study,it is found that the fluorescence emission spectra of(TTMAPP)have a significant correlation with the pH variation,and showed the characteristic of "isoemission point",of which the fluorescence intensity of TTMAPP was not affected by pH at a certain wavelength.The above-founding implied the possibility of TTMAPP to be a ratio fluorescence probe with strong anti-interference ability to achieve the purpose of more accurate determination of pH.The experimental conditions were optimized,and the characteristics of photo stability,reversibility and anti-ion interference of the probe were further investigated.We have applied TTMAPP probe to the determination of practical samples with satisfactory results.The responding mechanism was also discussed.A Logstic function model was introduced for the data processing.In the third chapter,it was found that copper ion(Ⅱ)had a highly selective and strong quenching effect on the fluorescence of TTMAPP,when carrying out the metal ion screening experiments,indicating that copper ion had a highly specific binding ability to TTMAPP.Based on these findings,TTMAPP was successfully developed as an optical probe for the determination of copper ion.Under the optimal conditions,the linear range of the calibration curve was 1.0 ×10-7 mol/L～1.0×10-6 mol/L.We have applied this method to the determination of food grade copper gluconate and the results were satisfied.The fourth chapter summarizes my contribution to the research work of Prof Yi’ s group as an exchange student in Shandong University.The research topic is the regulation mechanism of local renal inflammatory response,which provides important theoretical and experimental basis for finding new drug targets and prevention and treatment of kidney disease.