SILICA SURFACE INTERACTIONS OF DIOL-BONDED PHASES IN PACKED CAPILLARYCOLUMN SUPERCRITICAL-FLUID CHROMATOGRAPHY

3-Glycidoxypropyltrimethoxysilane (GPTMS), methyltriethoxysilane (MTES ), and 3-glycidoxypropyldimethylethoxysilane (GPDMES) bonded phases we re prepared for packed capillary column supercritical fluid chromatogr aphy (SFC). Additional active sites on the bonded surface were elimina ted using an end-capping reaction of 1,1,1,3,3,3-hexamethyldisilazane (HMDS). Hydrogen-bond interactions between the hydroxyl groups on the bonded phases and the residual silanols on the silica surface were inv estigated. The chromatographic performances of the bonded phases were investigated by the separation of polar organic compounds, including a lcohols, phenols, diols, ketones, aldehydes, esters, carboxylic acids, and amines, using packed capillary column SFC with neat CO2. (C) 1996 John Wiley & Sons, Inc.