Extraction and recovery of polycyclic aromatic hydrocarbons from environmental solids using supercritical fluids.

Abstract

The use of supercritical fluids for the extraction and recovery of polycyclic aromatic hydrocarbons (PAH) from environmental solids has been developed and tested by using urban dust, fly ash, and river sediment. Supercritical N/sub 2/O and 5% methanol modifier gave the best recoveries of PAH from all three samples when compared to supercritical CO/sub 2/ with 5% methanol, N/sub 2/O, CO/sub 2/, and ethane. Quantitative recovery of PAH from National Bureau of Standards SRM 1649 (urban dust) and of deuteriated PAH spikes (phenanthrene-d/sub 10/, pyrene-d/sub 10/, and perylene-d/sub 12/) from the river sediment was obtained with supercritical fluid extractions in as little as 30 min. In most cases, 30-60 min extractions of the river sediment and fly ash with supercritical N/sub 2/O/5% methanol gave better recovery of the deuteriated PAH spikes than the recoveries obtained by using 4 h of sonication or 8 h of Soxhlet extraction with either benzene or methylene chloride. Supercritical fluid extractions yield good PAH recoveries, require only small amounts of sample, minimize analyte concentration steps, and are simple and rapid to perform.