Synthesis Of Vinyl Functionalized Silica Sphere As Liquid Chromatographic Stationary Phase

High performance liquid chromatography(HPLC) is one of the most widely used devices in chemical analysis, and the chromatographic column packing material is a main component of the device. Nowadays, most packing materials of chromatographic columns are made by silica. However, the surface groups of direct synthesized silica packing materials are hydroxyl, which in lack of chemical activity to match with many kinds of modification techniques. Recently, ―thiol-ene‖ click reaction attracted lots of attention owing to its moderate reaction condition, high efficiency and environment friendly character. In order to effectively utilize this kind of modification technique in chromatographic packing material field, we have investigated the synthesis, modification and HPLC applications of vinly-functioned silica spheres(VFSS) in this work, which includes the following parts:(1) VFSS were synthesized through one-step method. The effects of reactant ratio, temperature, reaction time and ammonium hydroxide dripping speed were investigated. The diameter of the spheres reached 1.87μm magnitude by controlling the reaction conditions, which is suitable for HPLC packing material. Moreover, on the basis of the classic three steps model, we proposed a cycle-model to describe the synthesis process of VFSS.(2)The VFSS synthesized by one-step method were functionalized by C18 through ―thiol-ene‖ click reaction. VFSS and C18 modified VFSS(C-VFSS) were used as HPLC stationary phases to separate benzene homologs(benzene, toluene and meta-xylene) and nonpolar compounds with different ring contents(benzene, phenantherene and fluorantherene).Both VFSS and C-VFSS exhibited hydrophobic retention behavior. Additionally, vinyl groups in the silica spheres may offer a π-π electron-donor-acceptor(EDA) retention mechanism for chromatographic separation.(3)Grafting vinyl into mesostructured cellular foam(MCF) material to create a VFSS material, then utilize ―thiol-ene‖ click reaction to modify the material with sulfo group. This new method could effectively avoid the morphologic destruction of the typical oxidation modification method. The pore size of MCF material would not be changed by the new method, however, the surface area and pore volume would have a slight decrease after the modification.