Isolation and identification of mutagenic polycyclic aromatic hydrocarbons from a coal gasifier condensate

An iterative scheme of short-term bacterial mutagenesis assays and multidimensional liquid chromatographic methods was used to isolate mutagens from a neutral fraction of a complex carcinogenic tar formed as a by-product of coal gasification. Mutagens in the complementary reversed- and normal-phase liquid chromatographic fractions were identified by capillary column gas chromatography and gas chromatography-mass spectrometry. The principal mutagens included a variety of 4- to 6-ring unsubstituted polycyclic aromatic hydrocarbons, their alkylated homologs, and related methylene-bridged compounds. Most of the unsubstituted mutagens were known carcinogens that were qualitatively similar to those detected by carcinogenicity assays of fractions from other types of coal tars and cigarette smoke condensate. The chromatographic approach is generally applicable to complex mixtures and is especially well suited for fractionating mixtures of aromatic compounds and their alkyl homologs.