Extraction behavior of environmental organic pollutants in supercritical fluid extraction

Aiming at the development of a rapid-analysis technique for environmental organic pollutants on suspended particulate matter (SPM) in air, a supercritical fluid extraction (SFE) technique was studied. The extraction efficiencies of typical organic pollutants spiked in alumina particles were first examined at various combinations of the extraction temperatures and pressures. The recovery of polyaromatic hydrocarbons (PAHs) showed strong dependence on both the extraction temperature and the pressure. This result was disscussed in terms of the enhanced solubilities and desorption/diffusion rates at a higher temperature and pressure. As for n-octadecane and tetrachlorobenzene, they showed little dependence on the fluid conditions. This implied that solubility has little effect on the recovery in case of these compounds with relatively high vapor pressures. The extraction behavior was also investigated using real S,PM. Phthalates and Phenanthrene showed the maximum recovery at the highest temperature and pressure among three-step extraction, whereas n-alkanes and polysiloxanes were effectively extracted in the medium temperature and pressure step. The apparent difference in the extraction behavior implies the possibility of the selective extraction of the aimed analytes from real environmental samples.