Abstract: Packing materials for use in liquid chromatographs are prepared by reacting silica gel or porous glass having silanol groups on the surface thereof with a chemical modifier to chemically attach the chemical modifier to silanol groups on the silica gel or porous glass, and reacting the chemically modified silica gel or porous glass with an end-capping agent in gas phase at 250.degree.-500.degree. C. to chemically attach the end-capping agent to the residual silanol groups on the silica gel or porous glass.

Abstract: Disclosed herein is partially hydrophilicized silica gel which has hydrophobic groups such as octadecylsilyl group on the pore inside and silanol groups or hydrophilic organic groups on the surface. Also disclosed herein is a process for producing such silica gel.The silica gel has many applications as an adsorbent and catalyst carrier by virtue of the hydrophobic group and silanol group or hydrophilic organic group which are coexistent with each other. The silica gel is produced by performing plasma treatment on silica gel having hydrophobic groups on the entire surface including the pore inside, whereby eliminating the hydrophobic groups on the external surface and causing the silanol groups to appear.