| Capillary Electrophoresis (CE) is one of the most important and rapidly growing separation techniques in recent twenty years. It absorbed the virtues of both the conventional electrophoresis and modern High Performance Liquid Chromatography (HPLC). Although CE has a not long history, it has flourished in wide areas because of its inherent features, such as extremely small sampling volume, cheap instrumentation, high separation speed and efficiency. In recent years, CE has been extensively studied and applied as a highly effective analytical method in modern analysis. And excellent prospects of CE have been shown in the fields of pharmaceutical analysis, biochemical analysis, food analysis, and environmental analysis.However, the small sample injection volume and very thin capillary bring about difficulties to detections. The common used detection methods are Ultra-violet (UV), Laser Induced Fluorescence (LIF), Luminescence Detection and Mass Spectra (MS). Because amperometric detector (AD) is more sensitive than UV-visible detector and much cheaper than LIF detector, it is preferred to couple with CE in many analysis areas.Common amperometric detectors, based on glassy carbon or carbon paste electrodes, exhibit no response for many analytes because of a high overpotential. The benefits of using chemically modified electrodes (CMEs) in these systems include acceleration of electron transfer reactions, permselective transport, reduction in fouling, and preferential accumulation of analyte. Despite of these advantages of CMEs, no enough reports of their application in CE have appeared. The Goal of this dissertation is to apply CMEs into CE-AD technique to extend its application area and to improve the detection sensitivity. The contents of the dissertation include three chapters:In the first chapter, the characteristics of CE, the separation models, the injection technologies of CE, the detectors, the studies and applications of CE simply are introduced.Chapter 2 is the determination of four kinds of carbamate pesticides by capillary zone electrophoresis with amperometric detection at a polyamide-modified carbon paste electrode. In this paper, a polyamide-modified carbon paste electrode in CZE-AD was firstly applied to the determination of four carbamate pesticides:fenobucarb, isoprocarb, metolcarb and carbaryl. The four carbamates were hydrolyzed in alkalescent aqueous solutions, resulting in the formation of 2-sec-butylphenol, 2-isopropylphenol, m-cresol and α -naphthol, which could be determined by amperometry after capillary electrophoretic separation. Under the selected optimum conditions, the four analytes could be perfectly separated within 23 min. The linear ranges of 2-sec-butylphenol, 2-isopropylphenol and m-cresol were from 1.0×10-7 to 2.0×10-5 mol L-1 and that of α -naphthol was from 2.0×10-7 to 2.0×10-5 mol L-1 and their detection limits were 3.0×10-8, 3.0×10-8, 3.0×10-8 and 6.0×10-8 mol L-1, respectively (S/N= 3). Above results demonstrated that this method was of high sensitivity, good repeatability and could be used in the rapid determination of the pesticide residues.Determination of carbohydrates by capillary zone electrophoresis with amperometric detection at a nano-nickel oxide modified carbon paste electrode was reported in chapter 3. In this paper, a nano-NiO modified carbon paste electrode in capillary zone electrophoresis with amperometric detection (CZE-AD) was firstly applied to the determination of carbohydrates. Effects of several important factors such as detection potential, the concentration of running buffer, separation voltage and injection time were investigated to acquire the optimum conditions. Under the selected optimum conditions, three carbohydrates: glucose, sucrose and fructose could be perfectly separated within 20 min. The relationships between peak current and concentration of three carbohydrates were linear over about 3 orders of magnitude with detection limits (S/N = 3) ranging from 3.0×10-7 to 6.0×10-7 molL-1. The electrode was stable, and can be used for at least one week. The proposed method has been successfully applied to monitor carbohydrates in the real samples with satisfactory assay results.
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