| 1. PrefaceCapillary electrophoresis (CE) has been greatly developed and improved since its introduction. Now it has been widely applied in analytical chemistry, biological chemistry, food chemistry, environmental chemistry and so on, due to its speed, efficiency, reproducibility, ultra-small sample volume and ease of clearing up the contaminants. The introduction section deals with the basic principle, development history, actuality, trend and primary characteristics of CE. Capillary electrophoresis with electrochemical detection (CE-ED), as a new highly efficient technique, was rapidly developed last century. However, it also faces a lot of opportunities and challenges. Instrument needs further improvement in both reproducibility and sensitivity.The goal of this thesis is to explore some applications in traditional medicine analysis and biochemical analysis by CE-ED.2. A novel capillary electrophoretic method for determining methylglyxoal and glyoxal in urine and water samplesTwo non-electroactive biomarkers methylglyoxal and glyoxal in urine and environmental water samples were determined for the first time by capillary electrophoresis with amperometric detection (CE-AD) after derivatising with an electroactive compound 2-thiobarbituric acid. Experiment conditions of derivatization and CE-AD detection were optimized. The calibration curve was linear over a concentration range from 1.0 to 2000.0μg L-1 for MGo and 2.0 to 2000.0μg L-1 for Go with a correlation coefficient of 0.9996 and 0.9995, respectively. The detection limit of MGo and Go were 0.2μg L-1and 0.5μg L-1, and quantitation limit were 1.0μg L-1 and 2.0μg L-1, respectively. Recoveries varied from 90.9% to 101.3% and precisions, calculated as relative standard deviation (RSD), were better than 2.0%. The proposed CE-AD method does not require sophisticated analytical instruments and provides a reliable and sensitive quantitative evaluation of MGo and Go in real sample matrices. 3. Determination of Catecholamines and their metabolites in urine samples by Capillary Electrophoresis with Electrochemical DetectionCapillary electrophoresis with electrochemical detection (CE-ED) has been employed for the separation and determination of catecholamines and their metabolites in urine samples of several patients. 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. Good linear relationship was established between peak current and concentration of analytes over three orders of magnitude with detection limits (S/N=3) ranged from 1 to 5μg L-1 for all analytes. This proposed method has been successfully applied for the study on the diagnosis of Parkinson's disease, hypertension, diabetes, nephrotic syndrome and cancer (Non-Hodgkins Lymphoma, NHL), and the assay results were satisfactory.4. Determination of polyphenols in Valeriana wallichii DC by capillary electrophoresis with electrochemical detectionA high performance capillary electrophoresis with electrochemical detection (CE-ED) method has been developed for the analysis of eight bioactive ingredients in the leaf, stem and root of Valeriana wallichii DC after a relatively simple extraction procedure with ethanol. Under the optimum conditions, eight components can be well separated or nearly baseline separated (apigenin and luteolin peaks) within 23 min at the separation voltage of 16 kV in a 50 mM borax running buffer (pH 9.2).Notably, excellent linearity was obtained over two orders of magnitude with detection limits (S/N=3) ranged from 1.7×10-7 to 1.8×10-8 g/mL for all eight analytes. This method was also used for the comparison of the bioactive ingredient disparity in different parts of Valeriana wallichii DC based on their electropherograms or "electrochemical characteristic profiles", and the assay results were satisfactory.
|
PDF Full Text Request