Pressurized liquid extraction using water/isopropanol coupled with solid-phase extraction cleanup for semivolatile organic compounds, polycyclic aromatic hydrocarbons (PAH), and alkylated PAH homolog groups in sediment

Polycyclic aromatic hydrocarbons (PAH) are recognized as environmentally relevant for their potential adverse effects on human and ecosystem health. This paper describes a method to determine the distribution of PAH and alkylated homolog groups in sediment samples. Pressurized liquid extraction (PLE), coupled with solid-phase extraction (SPE) cleanup, was developed to decrease sample preparation time, to reduce solvent consumption, and to minimize background interferences for full-scan GC-MS analysis. Recoveries from spiked Ottawa sand, environmental stream sediment, and commercially available topsoil, fortified at 1.5-15 mu g per compound, averaged 94.6 +/- 7.8%, 90.7 +/- 5.8% and 92.8 +/- 12.8%, respectively. Initial method detection limits for single-component compounds ranged from 20 to 302 mu g/kg, based on 25 g samples. Results from 28 environmental sediment samples, excluding homologs, show 35 of 41 compounds (85.4%) were detected in at least one sample with concentrations ranging from 20 to 100,000 mu g/kg. The most frequently detected compound, 2,6-dimethylnaphthalene, was detected in 23 of the 28 (82%) environmental samples with a concentration ranging from 15 to 907 mu g/kg. The results from the 28 environmental sediment samples for the homolog series showed that 27 of 28 (96%) samples had at least one homolog series present at concentrations ranging from 20 to 89,000 mu g/kg. The most frequently detected homolog series, C-2-alkylated naphthalene, was detected in 26 of the 28 (93%) environmental samples with a concentration ranging from 25 to 3900 mu g/kg. Results for a standard reference material using dichloromethane Soxhlet-based extraction also are compared. (c) 2005 Elsevier B.V. All rights reserved.