A new facile method of preparing porous spherical silica particles as stationary phase for high performance liquid chromatography (HPLC) separations was developed. In this method, monolithic silica columns whose skeletons contained weakly connected porous silica microspheres were prepared first using the aging temperature and mass ratio of PEG to TMOS in the range of 25–30 °C and 0.10–0.20, respectively, and mass ratio of TMOS to H2O less than 0.5. Then, dispersed porous silica spheres were obtained by gentle grinding of the monolithic column. After surface modification with C18, silica microspheres with an average diameter of 5.4 μm were packed and used in HPLC for separation of neutral, acidic, and basic compounds. The retention behavior is similar to the column packed with commercially available 5 μm C18 silica particles while column efficiency is only about a half of the latter. The results demonstrate that the microspheres are a promising alternative packing material for HPLC.
