Study On Electrochemical Luminescence Properties Of Ruthenium Compound Modified Electrode

Electrochemiluminescence analysis（abbreviated as ECL）is a combination of electrochemical and chemiluminescence technologies,which involve the generation of species on the electrode surface that then undergo electron-transfer reactions to form excited states emitting light.Ru（bpy）₃²⁺and its derivatives have been widely applied in electrochemiluminescence analysis due to its high ECL efficiency,good sensitivity and electrochemical stability.In the conventional ECL test,luminescent material,such as Ru（bpy）₃²⁺,needs to be dissolved in the electrolyte,causing a lot of losses and increasing the test cost.In order to reduce the waste of luminescent materials and improve the ECL intensity,one of the most promising researches is to develop new functional electrode materials that possess the capability of immobilising ruthenium complex on the electrode surface.Part one:the situ encapsulated method was employed to encapsulate Ru（bpy）₃²⁺into the cavities of the water stable Uio-66 MOF that possessed high internal surface area and porosity,and then the composite material of Uio-66/Ru（bpy）₃²⁺was applied to modify glassy carbon electrode.The structure and morphology of the compound were characterized by X-ray diffraction,scanning electron microscope,ultraviolet spectrophotometer and so on.The results showed that Ru（bpy）₃²⁺was successfully loaded into the pores of Uio-66 and the crystal structure of Uio-66 remained intact.The electrochemical luminescence measurements showed that Uio-66/Ru（bpy）₃²⁺chemically modified electrode displayed good stability and luminescence performance,and could be further used for the detection of analytical substances.An ECL analysis method was developed for the quantitative detection of melamine by Ru（bpy）₃²⁺/Uio-66 modified electrode in the presence of quantitative N,N-dibutyl ethanolamine（DBAE）.The ECL intensity was proportional to log（melamine）concentration in the range 1.0×10^-15-1.0×10^-9 M with a detection limit of about 3.8×10^-1616 M（signal/noise=3）.Part two:a ruthenium compound containing pyridine dicarboxylate was designed and synthesized.The structure of the compound was proved to be correct by the ¹H-NMR spectrum and ¹³C-NMR spectrum.The ruthenium compound was directly immobilized onto the surface of ITO electrode by the strong adsorption of an anchoring group（pyridine dicarboxylate）.Then the ruthenium compound molecules were self-assembled on the surface of ITO electrode through the bridging action of“Sn”to form supramolecular compounds.By using this method,the ruthenium compound was directly immobilized onto the electrode surface without being bound by the carrier material,which further improved the electrochemical luminescence efficiency.Finally,what is investigated is the electrochemical luminescence response of ruthenium compound with different self-assembled layers to co-reactant tripropylamine（TPrA）,DBAE and melamine.The experimental results showed that the ECL property of the detection system was optimal,when the self-assembled ruthenium compound on the surface of ITO electrode were four layers（layer 4）.It has been proved that the self-assembled ruthenium compound on the surface of ITO electrode can be used as a new electrochemical luminescent substance to analyze the sample.