| Capillary electrophoresis (CE), namely high performance capillary electrophoresis (HPCE) is a highly efficient means of separation, which is performed in capillary tube and driven by electric field. It brings a profound revolution following the GC and HPLC, develops the analysis technology from a level of microlitre to nanolitre, and makes it possible to analyze a single cell and single molecule. CE has been proven to be one of the most powerful tools for the separation of protein, saccharide, chiral compounds, and the DNA sequencing, as well as single cell and molecule detection due to the advantages of high resolution, rapid analysis, small sample consumption, and simple instruments. However, the concentration sensitivity, especially for UV detection, is relatively poor because of the narrow internal diameter of capillary and small injection volumes. The problem has created a demand for a new form of detection, which would be relatively simple, widely applicable, provide quantitation, and be sensitive.The electrochemiluminescence (ECL) detection has the advantage of easy to control, excellent sensitivity, wide linear range, low reagent consumption, high reaction efficiency. Capillary electrophoresis coupled with electrochemiluminescence (CE-ECL), a new method with high separation efficiency and high sensitivity, is suitable for the analysis of trace components in complex biological and pharmaceutical samples.In this work, the studies on the analysis of ephedrae alkaloids by CE coupled with ECL detection have been described, and fabricated a new CE-ECL system by following its related principles. The main investigations are as follows.1. A new approach for the sensitive determination of a pair of diastereoisomeric sympathomimetic amines (ephedrine and pseudoephedrine) was established by CE-ECL. The conditions for the CE separation, ECL detection and the composition, concentration and pH of electrophoretic buffer were systematically investigated. The optimum conditions are listed as the follows:detection potential,1.2 V; electrokinetic injection,10 s for 10 kV; separation voltage,12 kV; 15 mmol/L phosphate-borax electrophoretic buffer at pH 7.4; 0.5 mmol/L Ru(bpy)32+ with 50 mmol/L PBS buffer at pH 8.5 in the detection cell. Under the optimal conditions, the two analytes were well separated within 5 min. The concentration detection limits of Ephedrine (E) and pseudoephedrine (PE) were 4.5×10-8 and 5.2×10-8 mol/L (S/N=3), respectively. The recoveries of E and PE at different levels in human urine samples were between 89.6% and 103.4%. The limits of quantitation (LOQ, S/N=10) in real human urine samples were 6.9×10(?)mol/L for E and 7.7×10(?)mol/L for PE, respectively. The precisions are less than 5.3%, respectively. The applicability of the method was demonstrated in analysis of urine, nasal drops, and the monitoring of pharmacokinetics. The proposed method has potential in quality control of pharmaceuticals and biochemical analysis.2. A new kind of CE-ECL detection system was developed; It was improved on the basis of traditional CE-ECL system, which was for the detection of ECL coreactants. However, the new developed CE-ECL system can not only be used for the detection of ECL coreactants, and also for the detection of ECL emanations and markers. What's more, it may be more widely used for the detection of protein bioactive substances and immune analysis. The application range and function of CE-ECL system were expanded.
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