Extraction of PCDD/PCDF from soil with supercritical CO2: Optimization by a three-level factorial design approach.

Two factors (pressure and temperature) varied over three levels were optimized for the extraction of PCDD/F from native contaminated soil with toluene-modified supercritical carbon dioxide. Temperature had a strong positive effect on the recovery. The most efficient extraction was achieved at 120 °C. This is in contrast to the influence of the temperature on the extraction of HCH, where a higher recovery is obtained at 60 °C than at 150 °C. The optimized conditions found for this soil were applied to the analysis of a BCR (European Commission) reference material prepared from contaminated industrial soil. The results are in good agreement with those of an interlaboratory study. [ABSTRACT FROM AUTHOR]