| Capillary electrophoresis (CE) is a new-style separation technique which was established and quickly developed in the early 1980s. Nowadays, CE has been widely used in the fields of chemistry, life science, pharmaceutics, environment analysis and so on, due to the advantages of higher separation power, short analysis time, small sample and reagent consumption and simplicity. There are many detection methodologies coupled with CE, such as UV-Visible detection (UV-Vis), Laser Induced Fluorescence detection (LIF), Electrochemical detection (ED) and Mass Spectrum (MS). Since ED has much advantage over other widely used techniques in that it is much more economical, without complicated pretreatment procedure, and it provides good selectivity as well as high sensitivity, it has flourished to various areas. Many medicaments and its effective components are electrochemical active, therefore, electrophoresis-electrochemical detection (CE-ED) method can be used to the separation and analysis of medicaments and its effective component. In this dissertation, we have carried out major innvative work on the base of previous work. The contents of this dissertation include four chapters:Chapter 1 In the first chapter, the preface has reviewed the history, the current situation and the future trend of capillary electrophoresis (CE). The fundamental theory of CE and the characteristics of CE, the separation modes, the detections coupled with CE are introduced. It also contains the applications of CE in drug analysis. The goal and significance of this dissertation are introduced, too.Chapter 2 In this section, a method based on capillary electrophoresis with electrochemical detection (CE-ED) had been developed for the determination of six kinds of active ingredients in Radix Astragali and its medicinal preprations. The analytes could be separated within 17 min in a 75cm length capillary at a separation voltage of 18 kV in a 10 mmol/L borate buffer (pH 8.2). A 300μm diameter carbon disk electrode generated good response at + 0.95V (vs. SCE) for all analytes. The relationship between peak currents and analyte concentrations was linear over about three orders of magnitude with detection limits (S/N = 3) ranging from 7.8×10-8 g/mL to 1.1×10-7 g/mL for all analytes. With relative standard deviations of less than 4% for both migration time and peak current (n=7), This proposed method has been successfully used for the determination of these analytes in real samples, and the assay result was satisfactory.Chapter 3 In this chapter, the determination of active ingredients (ferulic acid, vanillic acid, quercetin, caffeic acid and protocatechuic acid) of Polygonum perfoliatum L. by capillary electrophoresis with electrochemical detection was studied. CE-ED was successfully used to separate and detect the five active ingredients for the first time, and the experiment conditions were optimized. Under the optimum conditions, the analytes could be separated within 17 min at a separation voltage of 18 kV in 10 mmol/L phosphate buffer (pH 9.2). A 300 urn diameter carbon disk electrode generated good responses at + 0.95V (vs. SCE) for the five analytes. The response was linear over three orders of magnitude with detection limits (S/N = 3) ranging from 7.1×10-8 to 9.3×10-8 g/mL for the analytes. This proposed method could be successfully applied to the analysis of the real samples with relatively simple extraction procedures, and the assay results were satisfactory.Chapter 4 In this section, a method based on capillary electrophoresis with electrochemical detection (CE-ED) has been developed for the separation and determination of six sulfonamides (sulfaguanidine, sulfamethazine, sulfamerazine, sulfadimethoxine, sulfadiazine, and sulfamethoxazole) in feed. The effects of working electrode potential, pH and concentration of running buffer, separation voltage and injection time on CE-ED were investigated, and then the optimum experimental conditions were obtained.
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