Chemical fractionation of particulate extracts from diesel vehicle exhaust: distribution of ligands for the dioxin receptor

Diesel vehicle emission particulates were collected using a cyclone sampler. A solvent extract made from the particulate material was fractionated on the basis of polarity into five fractions (I-V). Fractions I and II were further subfractionated (I-1 and -2, II-1 to II-7). The amounts of 28 polycyclic aromatic compounds present in the extract and its fractions were measured. The ability of each fraction to compete with 2,3,7,8-tetrachloro[1,6- 3 H]dibenzo-p-dioxin (dioxin) for its receptor was determined. The majority of dioxin receptor binding activity was seen in the primary fractions II and III.