| Capillary electrophoresis (CE) or high performance capillary electrophoresis (HPCE) was emerged in 1980's as an effective separation and analytical technique. The separation of CE is performed within an elastic quartz capillary using high-pressure dc field as driving force. The different substances are separated based on their different mobility of electric field intensity or distribution of migration. The advantages of CE include high separation efficiency, short analysis time, small sample volume, and simple instrumentation. Because of small sample volume (nL) required, the detection methods for CE should have high sensitivity.Electrochemiluminescent or electrogenerated chemiluminescence (ECL) is the luminescence generated by relaxation of exited state molecules that are produced during an electrochemically initiated reaction. The substance can be quantified by the produced ECL signal. The ECL method possesses the advantages of both CL method, high sensitivity, wide linear range and simple instrumentation, and electrochemical analytical method, easy controllability and selectivity. Tris(2,2-bipyridyl) ruthenium(Ⅱ) (Ru(bpy)32+) is one of the most important and extensively used ECL systems for its good water-solubility, stable and high emitting efficiency, and reversible electrochemical behaviour. Under a certain potential, Ru(bpy)32+is oxidized to Ru(bpy)33+on the working electrode, and then Ru(bpy)33+ reacts with coreactant and produces the excited state Ru(bpy)32+*, which can release light by returning to the ground state.Analytical procedures combining CE separation with ECL detection have the characters of both efficient, rapid, selective of CE and sensitive, in situ detection of ECL, which has been applied in various fields, such as biology, medicine, pharmacy, clinical, environmental and food analysis.This thesis consists of two sections:review and research report.In the review section, the definition, basic process and elementary condition for ECL and the ECL reaction mechanism of Ru(bpy)32+was simply presented. The principle, separation modes, sample introducing method and detetion method for CE was briefly introduced. The analytical application of CE-Ru(bpy)32+-based ECL detection method was well summarized. In the research report secetion, the enhancing efffects of three amine-containing compounds, namely berberine hydrochloride, clenbuterol hydrochloride and salbutamol on the ECL signal of Ru(bpy)32+were found. The experimental factors on the CE separattion and ECL detection was thoroughly examined. New CE-ECL detection methods were established for the detemination of these substances. The proposed methods were applied to the analysis of real samples. The research section includes two parts.Part One. A new capillary electrophoresis with electrochemiluminescence detection method was established for the determination of berberine hydrochloride, based upon the enhancement of berberine hydrochloride on the ECL signal of (Ru(bpy)32+. The effect of experiment factors, including the detection potential, the concentration of Ru(bpy)32+, the concentration and the pH of buffer solution in detection cell, the concentration and the pH of running buffer solution, the running voltage, the injection voltage and the injection time, on the determination of berberine hydrochloride was carefully investigated. Under the optimum experimental conditions, the determination of berberine hydrochloride could be accomplished within 4 min. The linear range for berberine hydrochloride was 2.0×10-8-1.0×10-6 g/mL and the detection limit (S/N=3) was 5×10-9 g/mL. The relative standard deviations of the ECL intensity and of the migration time for seven injections of 5.0×10-7 g/mL berberine hydrochloride solution were 5.9% and 1.2%, respectively. The proposed method was applied to the determination of berberine hydrochloride in berberine hydrochloride tablets and Chinese traditional medicine Coptis Chinensis with satisfactory results.Part Two. It was found that clenbuterol hydrochloride and salbutamol can both enhance the electrochemiluminescence(ECL) of Ru(bpy)32+. Based on these observations, a new capillary electrophoresis-electrochemiluminescence (ECL) detection method has been developed to the simultaneous determination of clenbuterol hydrochloride and salbutamol. The effect of Ru(bpy)32+concentration, detection potential, the kinds, concentration and pH of buffer solution, running voltage, injection voltage and injection time, on the separation and detection of clenbuterol hydrochloride and salbutamol was carefully discussed. Under the optimized experimental conditions, a baseline separation for clenbuterol hydrochloride and salbutamol was achieved within 17 min. The linear ranges were 5.0×10-8-5.0×10-6 g/mL for clenbuterol hydrochloride and 1.0×10-7-1.0×10-5 g/mL for salbutamol. Detection limits were 1×10-8 g/mL and 5×10-8g/mL, respectively. The method was successfully applied to determination of clenbuterol hydrochloride and salbutamol in pig's feeds. |
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