Quantitative determination of heterocyclic amines in food products

Heterocyclic aromatic amines (HAs) may be formed during heat-processing of proteinaceous foods. All HAs are mutagenic in the Ames test, and many are animal and non-human primate carcinogens. The information on human dietary exposure is, therefore, of primary importance to accurately assess this health risk. A sensitive multiresidue method for quantifying ng/g HA levels, i.e., MeIQx, IQx, 7,8-DiMeIQx, 4,8-DiMeIQx, IQ, MeIQ, PhIP, Glu-P-1, Glu-P-2, Trp-P-1, Trp-P-2, A alpha C and MeA alpha C, in food products by high performance liquid chromatographic analysis with ultraviolet and fluorescence detection was developed. Isolation from cooked foods was performed in a three-step solid-phase extraction procedure using cartridges of diatomaceous earth, propylsulfonic acid silica and octadecyl silica. Quantitative analysis in food products was done using the standard addition quantification model. Levels of PhIP and A alpha C exceeding 100 ng/g were found in grilled fish as well as grill scrapings, whereas of the commercial products investigated less than 50% contained detectable levels of heterocyclic amines, generally MeIQx in the range of 1 to 5 ng/g. Few samples, e.g., some Process Flavours, needed further purification and more selective detection methods to increase the sensitivity of the assay. Such products were further purified by solid-phase extraction with TSKCM650 gel, and analyzed with thermospray liquid chromatography/mass spectrometry.