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With polyethylene glycol as a porogen, vinyltrimethoxysilane (VTMS) and tetramethoxysilane (TMOS) as silica precursors, a hybrid silica monolithic material was obtained under the catalysis of acetic acid and thermally decomposed urea. The silica monolithic material was ground by a ballmill, treated with tris(hydroxymethyl)aminomethane (Tris), then washed and dried to obtain silica particles with particle size~3 μm. The effects of different reaction conditions on the particle size, surface morphology and dispersibility of silica particles were investigated. When the volume ratio of TMOS to VTMS was 3:1, it was observed that silica particles with a pore diameter of 7.5 nm and a specific surface area of 245 m 2 /g were obtained. The resultant silica particles were modified by binding with chlorodimethyloctadecylsilane (C18) and by the thiol-ene click reaction to obtain a mixed-mode type stationary phase. The test results showed that the silica packing materials prepared in this work has certain applicability.

Large-pore silica microspheres were synthesized by utilizing weak cation exchange polymer beads as templates, N -trimethoxysilylpropyl- N,N,N -trimethylammonium chloride (TMSPTMA) as a structure-directing agent, tetraethoxysilane (TEOS) as a silica precursor, and triethanolamine as a weak base catalyst. The hydrolysis and condensation of the silica precursors occurred inside the templating polymer beads yielded polymer/silica composite microspheres. After the organic polymer templates were removed in the calcination step, large-pore silica microspheres were produced. The effects of different reaction conditions on the morphology, structure and dispersibility of the formed silica microspheres were investigated. It has been shown that when the volume ratio of TMSPTMA, TEOS and triethanolamine was 1:2:2, silica microspheres with pore size range of 50-150 nm and particle size around 2 μm were obtained. The as-prepared silica microspheres were then bonded with chlorodimethyloctadecylsilane (C18), packed into a 50 mm×4.6 mm column, and evaluated for the separations of some common standard proteins and soybean isolation proteins. The results showed that the large-pore silica spheres from this work have potentials for protein separation in HPLC.