Isolation of a highly mutagenic aminophenanthrene from a coal gasification process tar

A major portion of the mutagenic activity associated with products and by-products of coal conversion can be ascribed to nitrogen-containing bases. We improved the extraction efficiencies for three- to five-ring aromatic bases by extracting them with a mixture of methanol and aqueous HCl, rather than with aqueous HCl alone. A complex mutagenic basic fraction of a coal gasification process tar was successively fractionated using cation exchange and reversed phase high-performance liquid chromatography. The fractions were assayed for mutagenic activity and were chemically analyzed by gas chromatography and gas chromatography-mass spectrometry. Aminophenanthrenes were identified as major contributors to the mutagenicity of the basic fraction. Aminonaphthalenes, aminobiphenyls, and their alkyl homologs were also present but were not detected as principal mutagens.