The Application Of Capillary Electrophoresis With Electrochemical Detection In Analysis Of Chinese Traditional Herb And The Research Of Miniacture CE-AD

1. PrefaceThe first section 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 is applied in this work. In the second section, the equipment, the principles, the application extension and the developments of CE-ED are summarized in detail. The preface highlights CE application in analysis of traditional Chinese medicines, the related active ingredients include alkaloids, flavonoids, phenolic acids, glycosides and so on in the third section. In view of the studies on miniaturized capillary electrophoresis with amperometric detection in this thesis, integrated capillary electrophoresis (ICE) are summarized. The last one discusses the purpose and meanings of the work. Totally 232 references are cited in the preface.2. Determination of Polyphenolic Constituents in Valeriana jatamansi Jones by Capillary Electrophoresis with Electrochemical DetectionValeriana jatamansi Jones, distributed widely in southwest areas of China,has been used as a traditional Chinese medicine due to its hypnotic, tranquilizing and antiviral activities. A high-performance capillary electrophoresis with electrochemical detection (CE-ED) method has been developed for the determintion of five bioactive ingredients in Valeriana jatamansi Jones, namely diosmetin, kaempferol, apigenin, chlorogenic acid, and caffeic acid. The effects of several factors such as the acidity and concentration of running buffer, the separation voltage, the applied potential and the injection time on CE-ED were investigated. Under the optimum conditions, these five components can be separated in a 50.0 mmol/L borax running buffer (pH 9.23) within 23 min. A 300 μm diameter carbon disk electrode was used as the working electrode positioned carefully opposite the outlet of the capillary in a wall-jet configuration atCapillary Electrophoresis; Electrochemical Detection; Valeriana jatamansi Jones; PolyphenolsCapillary Electrophoresis; Electrochemical Detection; Herba Saussureae Involucratae; Electrochemical Characteristic Electropherograminfluencing the separation and detection processes were examined and optimized. The end-capillary 300μm Cu wire amperometric detector offers favorable signal-to-noise characteristics at a relatively low potential (+0.50 V vs. Ag/AgCl) for detecting sugars. Three sugars (sucrose, glucose and fructose) have been separated within 330 s in a 8.5 cm length capillary at a separation voltage of 1000 V using a 50 mM NaOH running buffer (pH 12.7). Highly Linear response is obtained for above compounds over the range of 5.0 ~ 2.0x102μg/ml with low detection limit, down to 0.8 ug/ml for glucose (S/N=3). The injection-to-injection repeatability for analytes in peak current (RSD<3.6%) and for migration times (RSD<1.4%) were excellent. The new miniaturized CE-AD system should find a wide range of analytical applications involving assays of carbohydrates as an alternative to conventional CE and μ-CE.