The solvent strength of supercritical fluid depends on the temperature and pressure of the extraction. Using this feature, simply change the pressure and temperature of fluid in the extraction, can the different components of the samples according to the size of the solubility in the fluid, successively extracted, weak polar material extraction, first under low pressure with the increase of pressure, larger and larger molecular weight of the material and the basic properties, so the supercritical extraction under the booster program, can get different extraction components, can also have the effect of separation.

Temperature changes in the density of extraction solvent and solute the vapor pressure of the two factors, the low temperature zone (still above the critical temperature), temperature to reduce the fluid density, and solute the vapor pressure increases, therefore, the solution ability of extracting agent temperature can make the solute precipitation from fluid extraction agent, and further raise the temperature to high temperature, although further reduce the density of the extractant, but increased solute steam pressure, increased volatility, instead, not only will not reduce the extraction rate has a tendency to increase.

En plus de la pression et de la température, la solubilité du soluté du fluide supercritique peut être modifiée en ajoutant une petite quantité d'autres solvants. Le mécanisme d'action n'est pas encore complètement compris. Généralement, la quantité d'addition ne dépasse pas 10%, et le solvant polaire méthanol, isopropanol, etc. sont majoritaires. L'application de la technologie d'extraction supercritique peut être étendue à des composés plus polaires en ajoutant une petite quantité de solvant polaire. 

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