SUPERCRITICAL-FLUID EXTRACTION COUPLED WITH IMMUNOAFFINITY CLEANUP FOR THE TRACE ANALYSIS OF ORGANIC POLLUTANTS IN DIFFERENT MATRICES

Supercritical-fluid extraction (SFE) has been investigated for the ext raction of organic micropollutants, including pesticides and polyaroma tic hydrocarbons (PAH) from soils and soot, respectively. Extraction r ecoveries for all the compounds studied were improved by optimization of conditions influencing extraction efficiency (e.g. pressure, temper ature, use of modifiers). Triazines and their polar metabolites were e xtracted from a native contaminated soil by use of carbon dioxide modi fied with a mixture of methanol and water. SFE was also applied to the extraction of more hydrophobic compounds, PAH, from certified soot. D ifferent types of modifier were used to enhance the extraction recover y. This optimization emphasizes the occurrence of strong interactions between the compounds and the matrix. Conditions were selected by adju sting the selectivity of the extraction to limit the co-extraction of interfering compounds. Remaining co-extracted compounds were removed b y cleaning the extract by immunoaffinity adsorption. This method enabl es achievement of the limits of quantification required for the two ma trices.