Silica surface interactions of diol-bonded phases in packed capillary column supercritical fluid chromatography

3-Glycidoxypropyltrimethoxysilane (GPTMS), methyltriethoxysilane (MTES), and 3-glycidoxypropyldimethylethoxysilane (GPDMES) bonded phases were prepared for packed capillary column supercritical fluid chromatography (SFC). Additional active sites on the bonded surface were eliminated 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 investigated. The chromatographic performances of the bonded phases were investigated by the separation of polar organic compounds, including alcohols, phenols, diols, ketones, aldehydes, esters, carboxylic acids, and amines, using packed capillary column SFC with neat CO2. (C) 1996 John Wiley & Sons, Inc.