Preparation And Evaluation Of Organic-silica Monolithic Column

The organic-silica hybrid monolithic columns have attracted great attention owing to combine the merits of the organic polymer and silica-based monoliths, such as ease fabrication, good mechanical stability and wide pH range tolerance. The methods and technology for the preparation of organic-silica hybrid monolithic columns have obtained great progress. It is very important to develop the novel organic-silica hybrid monolithic columns.There are four chapters in this thesis and the main contents which are listed as follows:In the first chapter, it reviewed the development of the capillary electrochromatography column technology. The progress on preparation and application of organic-silica hybrid monolithic capillary columns were introduced, as well as the content and significance of this program.In the second chapter, an epoxy-silica hybrid monolithic column was prepared by sol-gel process using TMOS and y-(glycidoxypropyl) trimethoxysilane as the precursors. This paper investigated the effect of the reactant ratio on the structure and performance of silica hybrid monoliths. A good mechanical stability, solvent resistance (K=5.95×10-14m2) and reproducibility (the RSD of batch-to-batch<6.6%, n=3) of the prepared epoxy-silica hybrid monolith were obtained. The column performances were carried out for both the neutral and charged analytes in hydrophilic interaction chromatography mechanism (HI-CEC mode). The separation efficiencies of charged nitroimidazole derivatives can highly reach 299,000 plates/m.In the third chapter, the hydrophilic silica hybrid monolith was successfully developd by introducing cyclodextrin modified iron oxide nanoparticles (MNPs-CD). The influences of organic modifier composition on the EOF of silica column and the retention mechanism of neutral solutes on the column were studied by pCEC mode. It also explored the separation mechanism of neutralmoleciles and ionic compounds. The prepared hybrid monolithic column has been applied to separation of the small neutral molecules (including toluene, DMF, amide and thiourea), phenol and aniline compounds. The efficiencies could get up to 91,710 plates/m which were higher than the epoxy silicahybrid monolithic column.In the fourth chapter, CP-silica hybrid monolithic column was prepared by sol-gel process using TMOS and 3-Chloropropyltrimethoxysilane (CPTMS) as the precursors. An o-phenantheoline-based immobilized ionic liquid (IILs)-type silica hybrid capillary monolithic column was successfully prepared on the basis of CP-silica. Compare with their electroosmotic flow (EOF) of both CP-silica and o-phenantheoline-based immobilized ionic liquid (IILs)-type silica hybrid capillary monolithic column, the latter was observed a stable reversed anode EOF in a broad pH ranged from 3.0 to 9.0. Meanwhile it investigated the performances of the organic-silica hybrid monolithic columns with different content of o-phenantheoline, which can obtain a significant reversed phase chromatographic performance. Various polar analytes including phenols and anilines were excellent separation in RP-CEC mode.