| Chromatographic column is the heart of High Performance Liquid Chromatography separation. Research and development on high performance stationary phase are therefore always the most active and popular subjects in liquid chromatography. And monodispersed silica spheres are the most widely used HPLC stationary phase matrix.Polymeric induced colloid aggregation (PICA) method and once-catalysis sol-gel method (Stober method) had been used to prepared 3-micron silica spheres respectively. Synthesis conditions were optimized with the test of microscopic particle image system and SEM. Experiments showed that, the condition to get regular and smooth spheres through PICA method was: pH=1.3 and silica:urea(l:2.5); in Stober method, depression of nucleation temperature and presence of little electrolyte led to particle size decrease of silica spheres.Tetraethoxysilane and ethyl silicate 40 had been used as raw material to prepare silica spheres by twice-catalysis sol-gel method. Productions were tested through SEM and particle size distribution instrument. And influences of factors such as water quality, alcohol concentration, rotary evaporation fashion, ammonia concentration, stirring speed, surfactant style and changes of raw material had been studied. Results of tests showed that the obtained silica spheres had smooth surface and the particle size distribution is Gaussian distribution; the silica spheres diameter increased with the increment of water quality and alcohol concentration, and decreased when stirred faster and added emulsifier.The molecular weight distribution of ethyl silicate and polyethoxysiloxane had been tested by Gel Permeation Chromatography. The analysis results reflected the conversion extent of raw material, intermediate products and final products objectively, providing valuable quantitative information for reaction process control. It is of certain guiding significance to resolve the difficulty of reproduction and further amplification experiments.
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