| Capillary electrophoresis（CE） is a new-style separation and analysis technique which isestablished and developed on the basis of biological science. On the analysis of biologicalsample, CE has showed unique superiority due to its low sample requirement andenvironment-friendly characteristics. Research on small functional molecules extensivelyexist in organism has become the hot point in CE field. Thiol containing molecules play anessential role in protecting cells against oxidative damage. New processes on sensitivedetection of thiols are sorely in need for the diagnosis of many emergent diseases, such asdiabetes mellitus and acquired immune deficiency syndrome （AIDS）. Several biologicalamines, like catecholamine, are considerable neurotransmitters in human body, by which thecentral nervous system has been accommodated and controlled. Accordingly, penetratinginvestigations on nervous system diseases, as Parkinson disease and schizophrenia, aredependent on the development of more efficient and reliable detection methods for bioamines.Sensitivity improving in CE remains heated among research works. Even though theemployment of mass spectrum, laser induced fluorescence and electrochemical detectorprovides an exceeding sensitivity, other devices aim to gain the amendment of sensitivity andselectivity, such as online sample concentration and design or modification of workingelectrodes in amperometric detection, are still of great interest. This thesis focuses on the CEdetection sensitivity of thiols and bioamines, working electrodes modification and onlinesample concentration is investigated to win higher sensitivity. The dissertation includes3chapters:Chapter1: PrefaceIn this section, overview of capillary electrophoresis-amperometric detection（CE-AD）,online sample concentration techniques for CE and advancements on analysis of thiols andbioamines by CE were generally introduced.Chapter2: Application of Modified Electrodes on Analysis of Typical Thiol ContainingBiomolecules by Capillary Electrophoresis with Amperometric Detector.A novel multi-walled carbon nanotubes modified carbon fiber microelectrode constructed with a simple method of chemical adsorption was employed in this work for thedetermination of thiols by capillary electrophoresis with amperometric detector. The effects ofseveral factors such as modifier amount and buffer characteristics were discussed. Under theoptimum conditions, excellent catalysis for the electrochemical oxidation of Glutathione（GSH）and Cysteine（Cys） was observed on this modified electrode while the limit of detection（LOD）reached to4.18×10-7mol/L2.39×10-6mol/L. In addition, catalytic capacity for thiols oftransition metal containing materials modified electrodes （nano-hydrogen copper oxidemodified carbon paste electrode and hybrid copper-cobalt hexacyanoferrate modified graphiteelectrode） was also been researched.Chapter3: Separation and Determination of Biological Amines in Banana Pulp by MicellarElectrokinetic Capillary Chromatography（MEKC）-Sweeping.A method based on micellar electrokinetic capillary chromatography （MEKC） combinedwith on line sample concentration technique-sweeping and amperometric detection wasdeveloped for the simultaneous determination of biogenic amines in banana pulp. A cathodalvoltage of-20kV was applied, the background electrolyte（BGE） comprised30mmol/Lphosphoric acid to inhibit the electroosmotic flow （EOF）, and30mmol/L sodium dodecylsulfate（SDS） to act as the factitious stationary face. Sample diluted in15mmol/L phosphoricacid was first injected into the capillary by siphonage, positive charged analytes were thenswept by negative charged SDS and focused on the boundary of sample zone and BGE, lastseparated by MEKC mode. Under the optimum conditions, the limit of detection （LOD） ofSerotonin （5-HT）, Dopamine （DA）, Norepinephrine （NE）, Tryptophan （Trp） and Tyrosine（Tyr） reached to8.69×10-8mol/L2.35×10-7mol/L. And this method had successfullyperformed in the analysis of biogenic amines in banana pulp. |
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