ABSTRACT
The solvating power of supercritical fluids is highly dependent on the density of the fluid. High fluid density in the supercritical fluid is achieved as a result of the high pressures created by the system rather than by intermolecular attraction as with liquids. The use of supercritical CO<sub>2</sub> has been demonstrated on analytical, preparative, and process scales for the separation, via extraction or chromatography, of high value products. The greater diffusivity of solutes in a supercritical fluid allows larger chromatographic resolution to be obtained, relative to that obtained using liquid chromatographic methods. Supercritical fluids have also been applied in the sterilization of enzymes and blood plasma powder, as an alternative to the use of heat, ethylene oxide, radiation, microwaves, and other methods. The safety of supercritical fluids for process-scale separations can be rationalized on the basis that they reduce the amount of highly flammable organic solvents which are used in conventional liquid extraction processes.
