Silica microspheres are of great interest in several areas such as liquid chromatography

medicine

biochemistry

colloidal chemistry and aerosol research. In this work

porous silica microspheres as packing matrix of HPLC were prepared from tetraethoxysilane (TEOS) by Sol-Gel method with carbon dioxide supercritical fluid drying technique. Conventional high-temperature vacuum dying (WO)

intermittent supercritical fluid drying (SCF-I) and continuous supercritical fluid drying process (SCF-C) were discussed. Silica microspheres were characterized by BET

TG-DTG

SEM

FT-IR

XRD and zetasizer analysis system. The results showed that the silica particles with spherical morphology were successfully prepared by all of the three processes and agglomeration was avoided. The specific surface area of silica microspheres was 69.04

268.40 and 513.41 m2·g-1 prepared by WO

SCF-I and SCF-C

respectively. The specific surface area of porous silica microspheres obtained by supercritical fluid drying was higher than that obtained by vacuum drying. SCF-I process was the optimum selection for the packing matrix of HPLC. Silica microspheres obtained by SCF-I were mostly regular-ball with specific pore volume of 0.5758 m3·g-1 without particle agglomeration. The mean particle size (D50) was 3 μm and the particle size distribution followed typical Gaussian distribution with a narrow particle size varied from 1 mm to 7 μm.