Various adsorbents have been investigated to separate complex organic mixtures. A second scheme is to use a single vessel but vary extraction parameters such as pressure and temperature to achieve clean-up followed by extraction. To understand SFE processes, an SFE kinetic model is being developed and is being tested by experiment. The model is derived from the theory for packed column chromatography. The model attempts to identify factors, including matrix components, that affect extraction rate.
Experiments have varied parameters such as temperature, pressure, modifiers and matrices.
One conclusion has been temperature and modifiers affect analyte-matrix interactions, so parameter optimization depends on both the analyte and the matrix. This study revealed matrix porosity was increased after SFE, indicating swelling and penetration by the supercritical carbon dioxide. J. Paw liszyn J. Chromatogr. Last revised September, 1998.