Application Of Fluorine-containing Organic Polymer-based Monolithic Column In Capillary Electrochromatography

Content: Capillary electrochromatography (CEC) is a relatively new micro-separation technique that combines the high efficiency of capillary electrophoresis (CE) and the high selectivity of high performance liquid chromatography (HPLC). Accordingly, it has attracted more and more attention in recent years. Up to now, monolithic columns have been considered as the most suitable stationary phases for CEC due to their simple preparation procedure, unique properties and no needs for frits.In traditional high-performance liquid chromatography, the polarity of the solute is roughly intermediate between those of the two chromatographic phases. The capacity factor and the general selectivity can be affacted by polarities of the three terms. Reasonable retention times and general selectivity can be obtained with mobile phase of adequate polarity, when the stationary phase polarity is kept constant. The lower the mobile phase polarity, however, the lower the capacity factor should be, and hence, the lower the selectivity of the chromatographic system becomes. To opposite is also true.In this thesis, a new low polarity of the fluorine-containing organic polymer-based monolithic(FCOPM) stationary phase was prepared by using 2-(N-ethyl perfluorooctanesulfonamido) ethyl methacrylate(QG-F814) as one of the polymerization monomers. The retention behaviors of several compounds on FCOPM stationary phase(low polarity) and conventional organic polymer-based monolithic(COPM) stationary phase(strong polarity) were compared under the same electrochromatographic experimental conditions. The results demonstrated that the retention decreases markedly on the FCOPM stationary phase with the selectivity slightly modified, provided that the mobile phase polarity is kept constant. The FCOPM stationary phase for the separation of biomacromolecules appears to be good in the reversed-phase capillary chromatography.Ultraviolet-visible spectrometry is the detection method most commonly used for CEC currently. In the present work, a homemade flow cell of U-shape was used for prolonging the optical path length, and consequently modifying the sensitivity. Also a simple method for coupling the U-shaped flow cell and the capillary monolithic column with the dead volume nearly zero was established, and thus the problem of easy breakage with the column can be resolved by simply replacing the broken flow cell with a new one.