| 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. Capillary electrophoresis-electrochemical detection (CE-ED) is an important complement technique of CE and expanded its application to many fields. Many medicaments and its effective components are electrochemical active, therefore, 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 seven chapters: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 its characters with minimal sample volume requirement, short analysis time and high separation efficiency are introduced simply. Electrochemical detection (ED) is applied in this work. The equipment, the principles, the application extension and the developments of CE-ED are summarized in detail. In this part, we also introduce the application of CE in drug analysis, chiral analysis and body-fluid analysis. In this part, we highlights the CE application in analyses of active ingredients and fingerprint spectrum of traditional Chinese medicines, and the related active ingredients include alkaloids, flavonoids, phenolic acids, coumarins, glycosides and so on. The goal and significance of this dissertation are introduced too. 208 references have been referred in this part.In chapter2, the determination of active ingredients of Ilex Purpurea Hassk by capillary electrophoresis with electrochemical detection was studied.Chinese traditional medicine ilex purpurea hassk belong to the family of Aquifoliaceae. Ilex Purpurea Hassk is widely distributed in south part of China, especially in Jiangsu, Zhejiang and Anhui Province. The dried leaves of this plant are known in China as 'sijiqing', and have been used ethnically as an effective crude drug in China for hundreds of years. It is used as a remedy (when given internally) to treat bronchitis, pneumonia and ulceration, and as an external treatment for scald, chilblain, etc. A method based on capillary electrophoresis with electrochemical detection (CE-ED) has been developed for the seperation and determination of isovanillic acid, gentisic acid, kaempferol, quercetin, caffeic acid and protocatechuic acid in Ilex Purpurea Hassk. The effects of working electrode potential, pH and concentration of running buffer, separation voltage and injection time on CE-ED were investigated. Under the optimum conditions, the analytes could be separated in a 50mmol.L borate buffer (pH=9.0) within 21 min. A 300μm diameter carbon disk electrode has a good response at +0.95 V (vs. SCE) for all analytes. The response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 3.0×10-8 g.mL-1 to 2.0×10-1 g.mL-1 for the analytes. The method has been successfully applied for the analysis of real sample, with satisfactory results.In chapter 3, the determination of epicatechin, isovanillic acid, vanillic acid, and myricetin in Dioscorea bulbifera L. by capillary electrophoresis with electrochemical detection was studied.Dioscorea bulbifera L. (commonly known as huangyaozi) is a member of the yam family Dioscoreaceae. The plant has been used as an herbal remedy for many years as an antispasmodic, analgesic, aphrodisiac, diuretic, and arejuvenative tonic. It has effects on the liver and heart and reduces carbuncles, lung abscesses, breast lumps, goitre, and tumors. Recently, Dioscorea bulbifera L. has been found to exhibit anti-tumor and anti-bacterial activity, anti-hypoglycaemic and anti-diabetic effects in vitro. Dioscorea bulbifera L. and its medicinal preparations are also used as clinical medicine to treat thyroid glands and tumors of different types. However, the use of Dioscorea bulbifera L. has been associated with higher incidence of liver damage. A method based on capillary electrophoresis with electrochemical detection has been developed for the separation and determination of epicatechin, isovanillic acid, vanillic acid and myricetin in Dioscorea bulbifera L. and its medicinal preparations. The effects of working electrode potential, pH and concentration of running buffer, separation voltage and injection time were investigated. Under optimum conditions, the analytes could be separated in a 40 mmol L-1 borate buffer (pH 8.7) within 15 min. A 300 μm diameter carbon disk electrode has a good response at + 0.95 V (vs. SCE) for all analytes. The response was linear over three orders of magnitude with detection limits (S/N = 3) ranging from 3.0 × 10-8 g mL-1 to 1.0×10-7 g mL-1 The method has been successfully applied to the analysis of real samples.In chapter 4, the determination of active ingredients of Origanum Vulgare L. and its medicinal preparations by Capillary Electrophoresis with Electrochemical Detection was studied.Origanum vulgare L. is a resilient perennial herb that belongs to the Labiatae family. Origanum vulgare L. can be found throughout Europe and Asia at elevations as high as 2000 meters. Origanum vulgare L. has been shown to possess high activity against both cancer and thrombin. The dried leaves of this plant are known in Chinese as "Niuzhi," and they have been used as an effective, albeit crude, drug to treat icterus, calenture, hepatitis, rheum, spew, and traumatism in China for hundreds of years. A method based on capillary electrophoresis with electrochemical detection (CE-ED) has been developed for the first time for the separation and determination of isovanillic acid, vanillic acid, quercetin, rosmarinic acid, caffeic acid, and protocatechuic acid in Origanum vulgare L. and its medicinal preparations. The effects of working electrode potential, pH and concentration of running buffer, separation voltage, and injection time on CE-ED were investigated. Under the optimum conditions, the analytes could be separated in a 50 mmol L-1 borate buffer (pH 8.7) within 21 min. A 300μm diameter carbon disk electrode has a good response at +0.95 V (vs. SCE) for all analytes. The response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 4.0×10-8g mL-1 to 2.0×10-7 g mL-1 for the analytes. The method has been successfully applied to the analysis of real sample, with satisfactory results.Chapter 5 is determining of active ingredients of Hawthorn by Capillary Electrophoresis with Electrochemical Detection.Chinese traditional medicine hawthorn belongs to the family of Rosaceae. Hawthorn is widely distributed in China, especially in Shandong, Hebei, Henan and Liaoning Provinces. The fruits of this plant are known in China as 'shanzha', and have been used ethnically as an effective crude drug in China for hundreds of years .It has long been used as a folk medicine and is described by many pharmacopoeias. Pharmacological and toxicological studies have demonstrated that consumption of hawthorn fruit is associated with long-term medicinal benefits on the cardiovascular function. Hawthorn extracts have beneficial effects on the heart and blood circulation including cardiovascular protective and hypotensive effects. A method based on capillary electrophoresis with electrochemical detection has been developed for the separation and determination of epicatechin, kaempferol, chlorogenic acid, 4-hydroxybenzoic acid, quercetin and protocatechuic acid in hawthorn for the first time. The effects of working electrode potential, pH and concentration of running buffer, separation voltage and injection time on CE-ED were investigated. Under the optimum conditions, the analytes could be separated in a 60 mmol·L-1 borate buffer (pH 8.7) within 21 min. A 300 μm diameter carbon disk electrode has a good response at +0.95 V (vs. SCE) for all analytes. The response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 3 × 10-8 to 2× 10-7 g·mL-1 for the analytes. The method has been successfully applied to the analysis of real sample, with satisfactory results.Chapter 6 is determining of active ingredients of Spatholobus Suberectus Dunn and Its Medicinal Preparations by Capillary Electrophoresis with Electrochemical DetectionThe Chinese traditional medicine, spatholobus suberectus dunn belongs to the family of Leguminosae. Spatholobus suberectus dunn is widely distributed in the south of China, especially in Guangdong, Guangxi, Yunnan Province. The dried rattans of this plant are known in China as "jixueteng", and have been used ethnically as an effective crude drug in China for hundreds of years. It is used as a remedy (when given internally) to treat irregular menstruation, hemopenia, and rheumatism. A method based on capillary electrophoresis with electrochemical detection has been developed for the separation and determination of epicatechin, emodin, syringic acid, vanillic acid, rhein, and protocatechuic acid in Spatholobus suberectus dunn and its medicinal preparations for the first time. The effects of a working electrode potential, pH and concentration of running buffer, separation voltage, and injection time on CE-ED were investigated. Under the optimum conditions, the analytes could be separated in a 60 mmol L-1 borate buffer (pH 9.0) within 26 min. A 300 μm diameter carbon disk electrode has a good response at +0.95 V (vs. SCE) for all analytes. The response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 5.0×10-8 gmL-1 to 2.0×10-7 gmL-1 for the analytes. The method has beensuccessfully applied to the analysis of a real sample, with satisfactory results.Chapter 7 is determining of amiloride hydrochloride and hydrochlorothiazide in compound amiloride hydrochloride tablets by CE-ED.Compound amiloride hydrochloride tablets are applied to the therapy of hypertension. A high-performance capillary electrophoresis with electrochemical detection method was developed for the determination of amiloride hydrochloride and hydrochlorothiazide in tablets and spiked human urine sample. Relevant parameters of the separation and electrochemical detection were examined and optimized. Under the optimum conditions, the two analytes could be well separated within 8 min at the separation voltage of 18kV in a 40mmolL-1 running phosphate buffer (pH8.0). A carbon disk working electrode, applying +1.0V (vs. Ag/AgCl, 3M KCl) as detection potential, was used to detect the two eletroactive analytes. The limits of detection of the two analytes were 0.08 and 0.10μgmL-1 respectively. The recoveries of the tablets samples were between 100% and 106%. The two standard analytes of certain concentration were spiked into blank human urine and detected, the recoveries were above 80%. The simple and efficient method was successfully applied to the compound amiloride hydrochloride tablets for some quality control purpose. The innovation of the dissertation lies on that we set up some new CE-ED methods which haven't been reported to separate and determine the active components in traditional Chinese herbs and their compound preparations as well as some curatives for hypertension. These methods are very effective, simple, fast, sensive, accurate and have some significances. At the same time, these methods provided many new scientific proofs for the guantitive control of Chinese medicine and the separation and determination of compound Chinese herbs. So that we can investigate the relationship between medicanment and their efficacy in multi-levels and consequently lead the research and exploitation of new medicines, and in the end establish a good base for the synthesization and selection of new medicines and medicine metabolize dynamics.
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