Application Of Capillary Electrophoresis Technology In Enzyme Assays And Sensitive Detection Of Drugs

Because of its high efficiency, high sensitivity, rapid analysis and low consumption, capillary electrophoresis has become a powerful platform for the analysis of enzyme reactions, and it is widely used in almost all aspects of enzymatic analysis. On the other hand, due to a variety of unique advantages, capillary electrophoresis is being more and more attention in trace detection of drug in recent years. In this paper, we carried out the application of CE in these two areas.The first part of this work is a novel method for online monitoring racemization reaction of alanine(Ala) enantiomers, which is developed by combining sequential sample injection and micellar electrokinetic chromatography(MEKC) technique. The system was constructed by passing two capillaries through a sample vial at a distance of 5 μm, depended on the fast in-capillary derivatization of amino acids and automatically control the switch of the separation voltage for reproducible sequential injection and online analysis; simultaneously, the efficient chiral separation and sensitive detection of the pair of enantiomers(substrates and products in the enzyme reaction) during the racemization were achieved by combining the sequential injection method with MEKC technique. The Michaelis constants of the racemization reaction(D-Ala→L-Ala and L-Ala→D-Ala) were obtained by the sequential MEKC method. Our study indicated that the sequential MEKC method can perform fast,efficient and accurate analysis of racemization reaction of amino acids, which is important to determine the activity of racemase and thus understanding its metabolic functions.The purpose of the second part of this work is to develop a rapid, efficient, and accurate analytical method to detect drugs, and it can provide strong evidence for prevent and combat-related criminal activities. By combining the advantages of capillary electrophoresis and field amplification sample injection(FASI), the experiment improved detection sensitivity. The laboratory homemade capillary-solid phase extraction column achieved a highly efficient enrichment and purification of the trace drugs, and then the enriched eluate of analytes were separated and detected by capillary electrophoresis. In the experiment, the capillary tip, which is stretched as solid phase extraction(SPE) column, filled with C18 extraction agents. Measurement of feasibility and effectiveness of the enrichment analysis is based on ephedrine and methamphetamine as the analysis targets.