EFFECT OF MOISTURE ON SUPERCRITICAL-FLUID EXTRACTION OF POLYNUCLEAR AROMATIC-HYDROCARBONS AND PHENOLS FROM SOIL USING AN AUTOMATED EXTRACTOR

An automated supercritical fluid extraction system was evaluated with polynuclear aromatic hydrocarbons and phenols to demonstrate extractio n efficiency, collection efficiency, and sample cross contamination. R esults showed that 75/25 glass beads/octadecyl silica provided the hig hest collection efficiency for these classes of compounds. Also, the a utomated SFE system was used to study the effect of different percenta ges of water (w/w) in soil on extraction efficiency of fortified PAH a nd phenols at different temperatures and pressures. Results showed tha t the presence of(available) water in soil (> 10%) does, increase extr action efficiency of higher molecular weight PAH at higher temperature . Also it was demonstrated that temperature rather than pressure had a marked effect on extraction efficiency. The extraction efficiency of phenols from soil which contained 5% of water, using pure supercritica l CO2, was higher than those obtained from dry soil or soil containing 1% water. Extraction of phenols from soil did not show a dependence o n pressure or temperature.