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.

Además de la presión y la temperatura, la solubilidad en soluto del fluido supercrítico se puede cambiar agregando una pequeña cantidad de otros solventes. El mecanismo de acción aún no se comprende completamente. Generalmente, la cantidad de adición no es más del 10%, y el disolvente polar metanol, isopropanol, etc. son la mayoría. La aplicación de la tecnología de extracción supercrítica puede extenderse a compuestos más polares agregando una pequeña cantidad de solvente polar. 

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