Study On ECL Behaviors And Mechanisms Of Some Nitrogen Heterocyclic Compounds

Nitrogen heterocyclic compounds are a class cyclic compounds that havecarbon and nitrogen as members of their rings. Nitrogen heterocyclic compoundshave been widely used in pesticides and pharmaceutical preparations due to theirhigh biological activity. Some nitrogen heterocyclic compounds play an importantphysiological role in plants and animals, as we are familiar with nucleotide bases,heme, chlorophyll and so on. As far as we know, ECL of nitrogen heterocycliccompounds has seldom been studied compared with alphatic amines. The study onECL mechanisms of these compounds is very important for studying biologicalelectron transfer reactions, intermediates’ stability and related intermediateproducts, and it’s helpful to reveal the oxidation meachanism of small biologicalmolecules.In this thesis, research on ECL behavior for nitrogen heherocyclic compoundswas carried out, based on which oxidation mechanisms of some nitrogenheterocyclic compounds were proposed. Furthermore, several rapid and highlysensitive flow injection electrochemiluminescent (FIA-ECL) detection methods fornitrogen heherocyclic compounds were established. The thesis consists of thefollowing four chapters:In the chapter1, the principle and application of ECL, the ECL of nitrogenheherocyclic compounds， and the principle and application ofspectroelectrochemistry (SEC) were briefly reviewed. And the methods forstudying ECL mechanism were also introduced. At last, the purposes and thesubject of this study were discussed.In the chapter2, research on FIA-ECL for five-membered nitrogenheterocyclic compounds was carried out. The research mainly includes designfabrication of FIA-ECL cell, and establishment of a FIA-ECL system for the ECLof the five-membered nitrogen heterocyclic compounds. The features of the thinlayer homemade ECL cell are as follows: very small dead volume, high sensitivity,good stability, and easy fabrication and installation. It can be used for FIA-EC, FIA-ECL detections, as well for HPLC-ECL detection. Under the optimumconditions, a sensitive and simple ECL method can be established for detecting3-methylpyrazole. The mechanisms of the five-membered nitrogen heterocycliccompounds were investigated and discussed.In the chapter3, research on FIA-ECL for several six-membered nitrogenheterocyclic compounds was done. A new FIA-ECL detection cell that can beeasily assembled with MPI-E ECL instrument has been developed. UV-Vis SECtechnology was introduced to study ECL mechanisms of cytosine, cytidine andthymine, and possible ECL mechanisms were proposed.In the chapter4, research on FIA-ECL for several fused nitrogen heterocycliccompounds was carried out. SEC behaviors of adenine, adenosine and guaninewere observed, and the oxidation intermediates and related products were studiedduring the oxidation process. ECL mechanisms of adenine, adenosine and guaninewere studied by combination of ECL and UV-Vis SEC.