Accelerated solvent extraction of semivolatile organic compounds from biomonitoring samples of pine needles and mosses

Accelerated solvent extraction (ASE) was used for the simultaneous extraction of semivolatile organic compounds (SOCs) including chlorobenzenes (1,2,3,4-tetra-, penta-, hexachlorobenzene), HCH isomers ([alpha]-,[Beta]-, [Gamma], [Delta]-, [Epsilon]-HCH), DDX (p,p[prime]-DDT, -DDE, -DDD), PCB congeners (28, 52, 101, 138, 153, 180), and PAHs (phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]pyrene) from mosses (Pleurozium sehreberi) growing in regional locations (central Germany) and pine needles (Pinus sylvestris L.) from southern Russia (near the Caspian Sea). The results were compared with those obtained by ultrasonic extraction (USE). Using mixed moss samples (thorough cleanup, only minor interference during GC/MSD analysis) from one location mainly served to optimize two parameters, extraction solvent and temperature. The most favorable extraction conditions proved to be n-hexane as the extraction solvent, two temperature stages of 40 and 120 [degrees] C, a pressure of 15 MPa, and three static cycles in each case. These conditions were then applied to the extraction of SOCs from the wax and the inner pine needle fraction, which beforehand had undergone extractive separation with dichloromethane. ASE was found to be especially advantageous in the case of higher multiple exposures to pollutants and the resultant complicated matrixes (oleiferous extracts, pollutant/matrix conjugates). Owing to the much better separation of analyte/matrix, in many cases increases of 1-2 orders of magnitude were obtained in the analytical values of the contaminated sample materials compared to those obtained with USE.