Where is supercritical fluid extraction going?

The status of supercritical fluid extraction as an analytical technique for treatment of solid samples is discussed. Its most significant advantages are its preconcentration effect, cleanness and safety, quantitativeness, expeditiousness and simplicity. Its limitations include the difficulty of extracting polar analytes, owing to the non-polar character of the CO2 which is used, the different recoveries obtained from spiked and natural samples, and the frequent need for clean-up steps after extraction. A critical discussion is given of these factors, as well as possible solutions and new alternatives such as the use of sub- and supercritical water and accelerated solvent extraction. (C) 2000 Elsevier Science B.V. All rights reserved.