TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Materials: The solid phase comprises sea sand, aminophases, cyanophases or silica gel.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The glyceryl ether is a polar glyceryl ether, preferably with a phosphorus group, or apolar glyceryl ether. The glyceryl ether preferably contains an alkyl group with at least 10C atoms and especially is selachyl alcohol (SA), batyl alcohol (BA) and/or chimyl alcohol (CA) or isomers. Carbon dioxide (CO2), dinitrogen oxide, ethylene, propane and/or ammonia are used as the supercritical fluid. Preferred Process: The process gives at least 2 PUFA fractions differing in their PUFA composition. The fatty acids in the mixture are esterified to monoesters, preferably ether esters, and these are separated into at least 2 fractions according to the number of C atoms and/or unsaturated bonds. The PUFA compounds are concentrated.The process uses carbon dioxide at 50-500 bar pressure and a temperature of 10-50degreesC. In extraction, the pressure is varied in stages, in which the pressure differs by at least 1 bar. After extraction with a supercritical fluid, the solid phase is also extracted with an organic solvent. ACTIVITY - Anabolic; Antibacterial; Cytostatic.    No biological tests or results are given.    MECHANISM OF ACTION - None given.    EXAMPLE - Selective extraction of chimyl alcohol (CA) from a fatty acid ethyl ester mixture was carried out with supercritical carbon dioxide (CO2). The extraction chamber was a stainless steel column, which was charged first with 15 g sea sand treated with 1 g fatty acid mixture and then with 160 g sea sand. The mixture was an ethyl ester mixture obtained from freeze dried biomass of Tetrahymena thermophila by esterification with ethanolic sulfuric acid. The mixture contained 5 wt.% CA and a mixture of 7 esters. The density (extraction strength) of the supercritical CO2 was adjusted so that only the esters were extracted from the mixture of sea sand. Extraction was carried out for 30 minutes at 40degreesC and a CO2 flow of 20 ml/min (80 bar). Analysis by thin film chromatography indicated that CA could be separated from the esters, so that no CA remained in the ethyl ester product.