| Electrogenerated chemiluminescence（also called electrochemiluminescence,ECL）,refers to the phenomenon of chemiluminescence generated during the process of applying a certain potential on electrode,the reactant undergoes an electrochemical reaction on the electrode surface to produce an excited state species,and when the excited state species returns to its ground state,the chemiuminescence signal was observed.Thus,the electrochemiluminescence analytical method not only has the advantages of simple equipment and high sensitivity of the chemiluminescence analytical method,but also has the advantages of the good controllability and fast analytical speed of the electrochemical analytical method.It has been paid much attention by the analyst and have been widely applied to the different analytical chemistry fields.Lucigenin is one of the most widely studied ECL reagent in the acridine-based ECL reagents,and lucigenin ECL system has been widely explored for different targets such as drugs detection and biological immunoassay.However,due to the poor water solubility of its ECL generating products and irreversibility electrochemical performances of Lucigenin ECL reaction,the sensitivity and stability of the lucigenin ECL system are obviously limited.Therefore,the development of the new and better ECL coreactants for lucigenin ECL system is very important.Based on this consideration above,the purpose of this thesis is to find new ECL coreactant in lucigenin ECL system,and further to improve the analytical performances of lucigenin ECL system.This thesis is mainly composed of two parts,the first part is review on the lucigenin ECL system in analytical application and the second part is my research work on searching for the new ECL coreactant in lucigenin ECL system and their analytical application.The review briefly introduced the ECL reaction principle of the conventional ECL systems,and mainly focused on the new development of lucigenin ECL system in analytical application.The research report is mainly composed of the following two aspects of research content:1.Detecting the sulfide ion based on its enhancement effect on the cathodic ECL signal of lucigenin.In this work,the effect of sulfide ions on the cathodic ECL of lucigenin was studied for the first time,and proposed the possible ECL enhancing mechanism.Based on this ECL enhancement,an new ECL analytical method for sulfide ions was established,which showed simple operation and high sensitivity.Under the optimal experimental conditions,the concentration of sulfide ion was linear with the enhancing ECL signal in the range of 1.0 X 10-10～9.0 ×10-9 mol/L,and the detection limit was 3.0×10-11 mol/L.This method was successfully used to detect sulfide ion in tap water by the recovery rate of 99%.2.Ratiometric ECL method for microRNA based on the controlled release of lucigenin from Lucigenin/Silica NPs with electrochemical method.In this work,we firstly found that in the pH 9.50 buffer solution,ECL resonance energy transfer（ECL-RET）could occur between lucigenin and the oxidation products of sulfide ions,which increase the anodic ECL signal significantly.The oxidation products of sulfide ions could also induce the controlled release of lucigenin in silica nanoparticles which produced cathodic ECL reactions.Based on this discovery and the distinguishing effect of functionalized silica nanoparticles on ssDNA and dsDNA,a sensitive ratiometric ECL method was established for microRNA.The concentration of let-7a was linear with the ratio of the enhanced ECL signal in the range of 1.0×10-13～9.0×10-12 mol/L,and the detection limit was 3.0×10-14 mol/L.This method was successfully used to detect microRNA in human serum samples by the recovery rate of 100%. |
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