Preparation Of The Fluorine-Containing Polymer Monolithic Stationary Phases For Capillary Electrochromatography

Content: Capillary electrochromatography (CEC) is a relatively new micro-separation technique that combines the high efficiency of capillary electrophoresis and the high selectivity of high performance liquid chromatography. Accordingly, it has attracted more and more attention in recent years. Currently monolithic columns are considered as the most suitable stationary phases for CEC due to their simple preparation procedures, unique properties and no need for frits, and it has been highlighted to develop new monolithic columns in the research on CEC. However, the vast majority of previous reports on CEC only concern the preparation of containing C-H bond monolithic stationary phases. Preparation of the fluorine-containing monolithic stationary phases hasn't been reported.In this thesis, we prepared two new types of fluorine-containing monolithic stationary phases by in-situ polymerization, all of them contain C-F bond and C-H bond. One of monolithic stationary phases was prepared by using the monomers of 2-(N-ethylperfluorooctanesulfonamido) ethyl methacrylate (QG-F814), butyl methacrylate (BMA) and 2-(dimethylamino)ethyl methacrylate (DAMA), the positive charged amine groups on the surface of the stationary phase generate an electroosmatic flow from cathode to anode. The effects of polymerization conditions on column performances were experimentally examined, and the optimal conditions for preparing the columns were established. The other of monolithic stationary phases was prepared by using the monomers of butyl methacrylate (BMA) and 2-(trifluoromethyl)-acrylic acid (TFMA), the negative charged acrylic acid groups on the surface of the stationary phases generate an electroosmatic flow from anode to cathode. The effects of polymerization conditions on column performances were experimentally examined, and the optimal conditions for preparing the columns were primarily established.The low surface energy of fluorine-containing monolithic stationary phases can reduce the nonspecific adsorption. In addition, fluoropolymers are insoluble in most common solvents and can be used in a wider range of pH values. They have high selectivity to some organic compounds, especially to fluorine-containing compounds, accordingly these fluorine-containing monolithic stationary phases not only have good potential to be used for highly selective separations of biomolecules and fluorine-containing pharmaceuticals, but also they are important to quickly separate hydrophobic large molecules by reversed-phase chromatography.