Standard Article

Supercritical Fluid Extraction of Inorganics in Environmental Analysis

Environment: Water and Waste

  1. Mehdi Ashraf-Khorassani1,
  2. Larry T. Taylor1,
  3. Michael T. Combs2

Published Online: 15 SEP 2006

DOI: 10.1002/9780470027318.a0870

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Ashraf-Khorassani, M., Taylor, L. T. and Combs, M. T. 2006. Supercritical Fluid Extraction of Inorganics in Environmental Analysis. Encyclopedia of Analytical Chemistry. .

Author Information

  1. 1

    Virginia Polytechnic Institute and State University, Blacksburg, USA

  2. 2

    3M Corporate Analytical Technology Center, St. Paul, USA

Publication History

  1. Published Online: 15 SEP 2006

This is not the most recent version of the article. View current version (12 MAR 2015)


Supercritical fluid extraction (SFE) of metal ions via in situ chelation and preformed metal chelates using pure or modified CO2 from several matrices has been accomplished. To understand the extraction results better, the solubilities of different ligands and metal chelates have been measured in supercritical fluids (SFs). In most cases, fluorinated chelates have been found to possess higher solubility in the SF than nonfluorinated ones, which in turn can often enhance extraction efficiency. Metal chelate stability under supercritical conditions plays an important role in the extraction of metals. Also, the matrix has a major effect on extraction efficiency of both hydrated metal ions and metal chelates. In order to obtain sufficient extraction not only should solubility of the metal complex be considered, but also the overall stability of the complex is critical.