An efficient and convenient method for the purification of mutagenic heterocyclic amines in heated meat products

A simple and efficient method for the purification of mutagenic heterocyclic amines from heated meat products has been developed. In only two steps, namely extraction of raw material on Kieselgur followed by medium pressure liquid chromatography on Sephasorb HP, very clean fractions with high recovery rates of mutagenic compounds were obtained, thus allowing isolation and quantitation by high performance liquid chromatography (HPLC) with UV detection. The method was validated on both food grade and bacterial beef extracts as well as fried beef. In 1-5 g samples of beef extracts, levels up to 70 p.p.b. (ng/g) of 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ), 8-90 p.p.b. of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and up to 8 p.p.b. of 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) were determined. In fried beef, 1 p.p.b. of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 1 p.p.b. of MeIQx were measured. The quantitative results of beef samples were in agreement with results from determinations using immunoaffinity chromatography/HPLC or liquid chromatography coupled with mass spectrometry. MeIQx could be quantified in fried beef down to 1 ng/g of fresh beef material. According to assays performed with reference standards of tryptophan and glutamic acid pyrolysis products, the method could also be extended to quantitate other heterocyclic amines.