Supercritical carbon dioxide in combination with silica gel to fractionateessential oils

Supercritical fluids have high selectivity thanks to the fact that their so lvating power can be varied either physically or chemically. Supercritical carbon dioxide (SC CO2) in combination with silica gel can successfully be applied to fractionate essential oils. By modifying the elation strength of SC CO2 through its density, several essential oils were fractionated, and it was possible to separate compounds of very similar polarity into differe nt fractions. In particular, the essential oils of Mentha x piperita L., Ta getes x lucida L. and Matricaria x chamomilla L. were processed. (C) 1999 J ohn Wiley & Sons, Ltd.