Study On Application Of Capillary Electrophoresis-electrochemiluminescence In Environmental And Pharmaceutical Analysis

Capillary electrophoresis(CE) with electrochemiluminescence (ECL) detection, as an high-efficient and high-sensitive analytical technique, has been extensively applied in the fields of pharmaceutical, biochemical, clinical and food analysis. But it is a pity that only a few studies on assay of environmental analytes have been reported by CE-ECL detection. On the other hand, the sensitivity and stability of a CE-ECL method will be greatly decreased since the surface of bare platinum working electrode is often contaminated by adsorbing sample matrices in biological fluids. Therefore, in this paper, a microdisk platinum electrode modified with europium (III)-doped prussian blue analogue (Eu-PB) film was used as a working electrode. Given this, a series of Ru(bpy)32+-based ECL detection coupled with CE have been established for the determination of polyoxin B absorbed in soils, ketotifen fumarate in pharmaceuticals and human urine, and lappaconitine hydrobromide, isopropiram fumarate in rabbit plasma. The present work would be helpful to the further development of detection methods for some environmental analytes and extend applications of CE-ECL technique.This paper consists of four chapters:Chapter One ReviewThe basic principles of CE and ECL are introduced firstly, and then the characteristics, the common systems and the application of CE-ECL technique in the fields of environmental and pharmaceutical analysis are summarized. Finally, the prospect of the newly developing techniques and further trends of CE-ECL methods are reviewed, and 116 references are cited.Chapter Two Determination of polyoxin B in soils by capillary electrophoresis - electrochemiluminescence detectionOn the basis of a chemically modified platinum electrode by europium (III)-doped prussian blue analogue film (Eu-PB) as a working electrode, a rapid and sensitive method for determination of polyoxin B was established using CE-ECL detection. Parameters related to the separation and detection were discussed and optimized. Under the optimized conditions, polyoxin B was separated within 4 min, and the ECL intensity was in proportion to polyoxin B concentration over the range of 1.0×10^-75.0×10^-7 g/mL and 5.0×10^-75.0×10^-5 g/mL with a detection limit (3σ) of 9.2×10-8 g/mL. The relative standard deviations (RSD) of intra-day and inter-day ECL intensity and migration time were less than 5.0 %. The proposed method was successfully applied in the determination of polyoxin B absorbed in three kinds of soils (e.g. bentonite, kaolinite and loess) with the recoveries of 92.2 % ¹04.3 %. The results also showed that the adsorption rate of polyoxin B in soils for 2 h was 89.0 % for bentonite, 45.5 % for kaolinite and 40.4 % for loess, respectively, indicating that the adsorption capacity of polyoxin B in different soils was bentonite> kaolinite>loess. The possible reason was related to the characteristics, specific surface area and cation exchange capacity (CEC) of soils.Chapter Three Determination of ketotifen fumarate in pharmaceuticals and human urine by capillary electrophoresis - electrochemiluminescence detectionOn the basis of a chemically modified platinum electrode by europium (III)-doped prussian blue analogue film (Eu-PB) as a working electrode, a simple, rapid and sensitive CE-ECL method was developed for the determination of ketotifen fumarate (KTF). The effects of several factors such as the applied potential, the acidity and the concentration of running buffer, separation voltage, and injection conditions on the detection were investigated. Under the optimized conditions, the ECL intensity was in proportion to KTF concentration over the range of 3.0×10-8².0×10^-6 g/mL and 2.0×10^-65.0×10^-6 g/mL with a detection limit (3σ) of 2.1×10-8 g/mL. The relative standard deviations of the ECL intensity and the migration time were 0.95 and 0.26 %, respectively. The developed method was successfully applied to the determination of KTF contents in pharmaceuticals and human urine with the recoveries between 99.5 and 107.0 %.Chapter Four Simultaneous determination of lappaconitine hydrobromide and isopropiram fumarate in rabbit plasma by capillary electrophoresis - electrochemiluminescence detectionA rapid and sensitive method for simultaneous determination of lappaconitine hydrobromide (LH) and isopropiram fumarate (IF) has been firstly established by CE - ECL detection. The effect of analytical conditions, such as applied potential, the pH and concentration of running buffer,separation voltage, injection voltage and injection time were investigated in detail. Under the optimized conditions, a baseline separation for the two analytes was achieved within 6 min, and the ECL intensity was in proportion to LH and IF concentration over the range of 1.0×10^-75.0×10^-6 g/mL and 5.0×10^-65.0×10^-5 g/mL for LH and 4.0×10^-85.0×10^-7 g/mL and 5.0×10^-71.0×10^-5 g/mL for IF with a detection limit (3σ) of 6.6×10^-8 g/mL for LH and 3.7×10^-8 g/mL for IF, respectively. The applicability of the proposed method was illustrated for the determination of LH and IF in rabbit plasma with recoveries between 95.6 and 103.0 %.