SUPERCRITICAL-FLUID EXTRACTION IN ENVIRONMENTAL-ANALYSIS

Supercritical fluid extraction (SFE), usually with carbon dioxide and often with a modifier. is a rapid, selective and convenient method for sample clean-up in environmental analysis. Three inter-related factors influence analyte recovery in SFE: solubility in the fluid, diffusion through the matrix and adsorption in the matrix. SFE may be coupled on-line to various analytical methods: gas, liquid and supercritical fluid chromatography. A wide range applications of SFE from environmental samples is described: hydrocarbons, chlorobenzenes and chlorobiphenyls, dioxins and chlorinated pesticides, herbicides and ionic surfactants. Organic compounds may be concentrated from air and water and extracted from adsorbents by SFE. Direct SFE from water is also possible.