The Application Of Capillary Electrophoresis With Electrochemical Detection In Pharmaceutical Analysis

Pharmaceutical analysis is very important for the pharmaceutical identification, quality control and clinic study. So it is quite needed to develop an analytical method with high separation efficiency and high detection sensitivity.Capillary electrophoresis (CE), as a powerful analytical separation technique, has been widely used in pharmaceutical analysis. It has many advantages, such as high separation efficiency, good selectivity, rapid analysis time, low cost as well as low consumption.Electrochemical detection (ED) is a detection method based on the electrochemical reaction of the analytes occurred on electrode surface. It has a great deal of advantages including high detection sensitivity, high selectivity, simple instrumentation and so on. Thanks to these advantages of CE and ED, capillary electrophoresis-electrochemical detection (CE-ED) is extensively studied and widely applied in the field of analytical chemistry.This thesis studies the application of CE-ED detection technique in pharmaceutical analysis. Based on this technology, the main work of this thesis is summarized as follows:1. Carvedilol, an antihypertension drug, was analyzed by CE-ED at a carbon fiber microdisk electrode (CFE). The linear range (r = 0.9987) of carvedilol detection was 0.01-8.0μM, and the limit of detection was found to be 1.0 nM. By making repetitive injections of 1.0μM standard solution of carvedilol, the relative standard deviations (RSD) of the migration time and peak current were 0.47% and 3.04% (n = 5). The method was also successfully applied for the determination of carvedilol in pharmaceutical table. The recoveries obtained varied from 98.0% to 103.5%, and the results are satisfying.2. CE-ED was applied for the separation and determination of three thyreostatics drugs at a CFE, including carbimazole (CBI), 6-propyl-2-thiouracil (PTU) and 6-methyl-2-thiouracil (MTU). These three compounds could be well separated within 8 min in 20 mM phosphate buffer solution (pH 8.0). The proposed method displayed a wider linear detection range and lower detection limi. The CE-ED technique has been successfully applied to analyze the above three compounds in human urine samples and the results are satisfying.