Preparation And Evaluation Of CEC Column With Special Structure

The high column efficiency and high selectivity of Capillary Electrochromatography (CEC) depend on the structure of the column and the property of the separation mediums. Nanomaterials have many advantages such as large surface area and the easily modified surface. Designing unique chromatographic columns using nanoparticles as stationary phase, constructing novel chromatographic column system, and developing universal separation and analysis methods through high performance capillary electrophoresis are of great significance.The anion-exchange, strong cation-exchange and reversed-phase chromatography stationary phases were prepared through different surface modification of core-shell Fe3O4@SiO2 nanoparticles respectively. A novel CEC column was prepared by using a couple of permanent magnets to immobilize magnetic chromatography stationary phases which have good magnetic response and can be easily operated. The CEC column with anion exchange stationary phase was used to optimize the separation conditions of organic acids, and its application to the separation of Gastrodia elata extract shows good separation capacity. The characterization of Fe3O4@SiO2 nanoparticles shows its particle size is 100 nm, and saturation magnetization rate is 41.2 emu/g. And Infrared spectrum also shows sulfonic acid group has been successfully introduced on the surface of Fe3O4@SiO2. The preliminary evaluation of separation performance of the CEC column prepared by strong cation-exchange stationary phase was conducted. A CEC column with a mixed-mode stationary phase was prepared by mixing anion-exchange and reversed-phase stationary phases with different ratio. The characteristics of EOF were theoretically investigated. The experiment was conducted under different ratio of mixed-mode stationary phase and different pairs of magnets to veify the theory. The results shows that the theoretical conclusions accord with the experimental results. Both theoretical and experimental investigation show that EOF can be easily adjusted by changing the ratio of stationary phase or the number of magnets.This paper also constructed three types of immobilized pH gradient monolithic columns, and prepareed a novel packed capillary column with immobilized pH gradient using porous silicon as matrix, which were applied to the separation of proteins. The results indicate potential application value of them in the study of proteins.