C 18 functionalized mesoporous silica SBA 15 with a high surface area was applied in high performance liquid chromatography(HPLC) to separate small biomolecules: cysteine, glutathione, dopamine and 6 thiopurine. Compared to commercial available C 18 column, C 18 SBA 15 has a much higher surface area, which enhances the capillary HPLC resolution by increasing molecular capacity factors. The uniform distributed mesopores in SBA 15 result in HPLC peaks narrower than that of commercial colum...