Class separation of mutagenic polycyclic organic material in grilled and smoked foods

A method for class separation of mutagenic polycyclic organic material in grilled and smoked foods is described. The procedure involves an initial extraction with acetone, removal of fat and proteins by precipitation at -55 degrees C, and an acid-base extraction. Further fractionation was carried out by gel filtration and silica gel chromatography. In four samples of grilled sausages, 80%-90% of the extracted mutagenicity (TA98 + S9) was contained in the basic fractions. Flame-grilled sausages showed higher mutagenicity than charcoal-grilled ones. In a smoked fish sample, the mutagenicity was low and evenly distributed between the basic and the neutral/acidic fractions. A few samples showed a weak direct-acting mutagenicity in the neutral/acidic fractions. The presence of nitrite in grilled sausages did not influence the mutagenicity markedly. Gas chromatography-selected ion monitoring was used to successfully identify a number of polycyclic aromatic hydrocarbons (PAHs) and tentatively identify several nitro-PAHs and oxygenated compounds. However, the identification of mutagens in the basic fractions was complicated by peak tailing and the presence of co-eluting material.