Submitted to: Liquid Chromatography International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: September 15, 1996
Publication Date: N/A
Technical Abstract: There is increasing use both in theory and application of chromatographic concepts in SFE. For example, various chromatographic theories have been used by investigators to explain the dynamics of SFE, while SFF (supercritical fluid fractionation) utilizing chromatographic sorbent media can be classified and explained by the solubility parameter theory or surface energetic approach be used to qualitatively explain extraction profiles generated and the retention of analytes (sorbates) during both analytical and process SFE. The limited specificity of SFE when using CO2 as an extraction fluid has forced analytical chemists to employ different types of chromatographic sorbent media in modes ranging from elution, displacement, and frontal analysis. Experimentally, chromatography during SFE can be performed in the extraction cell, in a post extraction sequence, for trapping purposes, and inversely to remove unwanted coextracted solutes. Considering the low elutropic strength of SC-CO2, the adsorption mechanism of retention is prominent, but examples will be cited that show the presence of a diminutive size exclusion mechanism in some instances. Certainly, solute retention in SFE and SFF is governed by similar factors present in chromatography, namely solute solubility in the SF phase and adsorption at the fluid-sample or -sorbent interface, which is a sensitive function of solute molecular structure.