BIOASSAY-DIRECTED FRACTIONATION OF ORGANIC-COMPOUNDS ASSOCIATED WITH AIRBORNE PARTICULATE MATTER - AN INTERSEASONAL STUDY

Bioassay-directed fractionation based upon a modification of a publish ed technique is applied to the study of three seasonal composites of d ichloromethane extracts of inhalable particulate matter collected in N ewark, New Jersey. The ''profiles'' of mass distribution and Salmonell a TA98 mutagenic activity vs polarity are similar for the three season s. Only at the second and especially the third fractionation levels ar e significant differences seen with a slight shift toward more polar c ompounds during summer. In all three seasons, polar neutral compounds make the greatest contribution toward mutagenic activity. Hydroxynitro polycyclic aromatic hydrocarbons are difficult to analyse by GC/MS) (E I and negative chemical ionization), but HPLC/UV appears to be useful. A number of techniques are employed in the analysis of specific compo unds and classes of compounds. Subsequent acetone extraction of filter s yields highly polar mutagens where the acidic fractions account for most of the mutagenic activity. These compounds show significantly enh anced mutagenic activity with TA100 relative to TA98 suggesting the pr esence of highly polar, acidic substances that are strong alkylating a gents. The compound 2-acetoxy-1-nitronaphthalene, found in fresh diese l particulates, is shown to hydrolyse during fractionation, thus intro ducing a note of caution into the use of such procedures.