Analysis of nonpolar heterocyclic amines in cooked foods and meat extracts using gas chromatography-mass spectrometry.

Heat processing of muscle foods gives rise to the formation of mutagenic and carcinogenic heterocyclic amines, often at ng/g levels. A gas chromatographic-mass spectrometric (GC-MS) technique was introduced for the analysis of nonpolar heterocyclic amines in common cooked meats, pan residues, and meat extracts after solid-phase extraction. The mutagenic heterocyclic amines 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-9H-pyrido[2,3-b]indole (A alpha C) and 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeA alpha C) were identified in several samples in amounts up to 8 ng/g. Also the comutagenic substances 1-methyl-9H-pyrido [3,4-b]indole (harman) and 9H-pyrido[3,4-b]indole (norharman) were detected in the samples in amounts up to almost 200 ng/g. The GC-MS method can be applied without derivatisation of the sample. The technique offers high chromatographic efficiency, yielding detection limits for pure references in the range 0.1-2 ng per injection.