AQUEOUS EXTRACTION OF AIRBORNE PARTICULATE MATTER COLLECTED ON HI-VOLTEFLON FILTERS

An extraction method was developed for the quantitative recovery of fi ne particles collected on Hi-Vol Teflon filters and in a form suitable for assessment of the biological reactivity of atmospheric aerosols. Two major criteria identified for the selection of a procedure were ma ximum recovery and minimization of the introduction of chemicals into the extract solution. Experiments were conducted with different volume s of a pre-wetting agent (ethanol) and sonication times to select the appropriate conditions for the aqueous extraction of material from the hydrophobic Teflon surface. The developed procedure involved the pre- wetting of a filter (cut into 8 pieces) with 2 mL ethanol and sonicati on in 400 mL ultra pure water for 30 minutes. Results of gravimetric a nalyses indicated high mass recoveries (91+/-7%) of material from the Teflon filters. Analyses for polycyclic aromatic hydrocarbons (PAHs) w ere performed on organic extracts of portions of Teflon filters with p articles and portions of the same filters subjected to aqueous extract ion. Comparison of the results revealed high percentages (92+/-11%) of PAHs were transferred into the aqueous solution using the extraction method developed. Inorganic analyses performed on Teflon filters (load ed with particles) and freeze-dry residues of aqueous extracts of Tefl on filters also suggested high transfer rates (84+/-33%) of inorganics into the aqueous extracts.