PREPARATION AND EVALUATION OF OCTADECYL TITANIA AS COLUMN-PACKING MATERIAL FOR HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Previously, we have found that titanium dioxide (titania) is a promising column-packing material for high-performance liquid chromatography because it shows a high resistance to both acid and alkaline eluents and has much larger absorption capacities than silica gel. In this investigation, octadecyl titania (ODT) was prepared by reacting n-octadecyltriethoxysilane with titania to apply it to a column-packing material for reversed-phase high-performance liquid chromatography. ODT proved to be stable in a wider range of pH's than octadecyl silica, giving reversed-phase separation for indissociable solutes such as aromatic hydrocarbons and parabens. In addition to the reversed-phase partition, however, the retention on ODT was governed by electrostatic interaction (ionic, hydrogen bonding, etc.) of solutes with titania as well, probably due to the existence of titanol (=Ti-OH) groups and positive and negative charges on its surface. (C) 1994 Academic Press, Inc.