Fused silica capillaries with an i.d. of 50 and 75 μm are chemically modified by the silanization/hydrosilation method to attach organic moieties for use in electrokinetic chromatography. An etching process was utilized to increase the surface area of the capillary inner wall. A comparison of Si-C bonded capillary columns to those obtained by conventional organosilanization (Si-O-Si-C) bond was performed. The etched capillaries after chemical modification are shown to have an anodic electroosmotic flow (EOF) below pH 4.5 while the bare modified capillaries show a cathodic EOF at all pH's studied.