Supercritical-fluid extraction coupled with immunoaffinity clean-up for the trace analysis of organic pollutants in different matrices

Supercritical-fluid extraction (SFE) has been investigated for the extraction of organic micropollutants, including pesticides and polyaromatic hydrocarbons (PAH) from soils and soot, respectively. Extraction recoveries for all the compounds studied were improved by optimization of conditions influencing extraction efficiency (e.g. pressure, temperature, use of modifiers). Triazines and their polar metabolites were extracted from a native contaminated soil by use of carbon dioxide modified with a mixture and methanol and water. SFE was also applied to the extraction of more hydrophobic compounds, PAH, from certified soot. Different types of modifier were used to enhance the extraction recovery. This optimization emphasizes the occurrence of strong interactions between the compounds and the matrix. Conditions were selected by adjusting the selectivity of the extraction to limit the co-extraction of interfering compounds. Remaining co-extracted compounds were removed by cleaning the extract by immunoaffinity adsorption. This method enables achievement of the limits of quantification required for the two matrices.