title: Modifier adsorption in supercritical fluid chromatography onto silica surface.
abstract: The adsorption of methanol, ethanol and isopropyl alcohol on a silicagel adsorbent from supercritical carbon dioxide was investigated using nonlinear chromatographic techniques. Series of adsorption isotherm data points of these alcohols were determined by frontal analysis. Their nonlinear adsorption behavior were modeled using a modified BET equation extended for heterogeneous adsorption surfaces. Our results suggest the formation of an adsorbed multilayer of alcohols above the silica surface. This organic solvent enriched layer governs the separation of the analytes in supercritical fluid chromatographic separations, both under analytical and preparative conditions.
authors.affiliation: Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, USA.
authors.forename: Péter
authors.initials: P
authors.lastname: Vajda
authors.forename: Georges
authors.initials: G
authors.lastname: Guiochon
mesh_terms: D000327:Adsorption; D000438:Alcohols / Q000032:analysis; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D000438:Alcohols; D012822:Silicon Dioxide
keywords: Frontal analysis; Modifier adsorption; Supercritical fluid chromatography