Pressurized hot water extraction (PHWE) of n-alkanes and polyaromatic hydrocarbons (PAHs): Comparison for PAHs with supercritical fluid extraction

High-temperature liquid water and steam were used to extract n-alkanes and polyaromatic hydrocarbons (PAHs) from spiked sea sand at different temperat ures. Pressurized hot water extraction (PHWE) was followed by solid phase c ollection. Tenax as the trapping material with Iz-heptane as the eluent gav e recoveries larger than 95% for diesel hydrocarbons extracted with steam a t 250 degrees C. Recoveries from Tenax of hydrocarbons extracted with liqui d water under the same conditions were lower. Good (>90%) recoveries were a lso obtained for low molecular weight PAHs. extracted with steam at 250 deg rees C and with n-heptane as eluent for the Tenax trap. n-Heptane containin g 10% ethyl acetate was more efficient, eluting high as well as low molecul ar weight PAHs with good recovery. PHWE was also tested in the extraction o f a real sediment sample certified for PAHs, and the results were compared with those obtained with supercritical fluid extraction (SFE) using neat CO 2 and modified CO2. Steam at 250 degrees C and 300 degrees C gave similar r ecoveries as those obtained by SFE with use of a modifier. (C) 2000 John Wi ley & Sons. Inc.