ELSEVIER Journal of Chromatography A, 763 (1997) 179-185 JOURNAL OF CHROMATOGRAPHYA Analysis of foods for heterocyclic aromatic amine carcinogens by solid-phase extraction and high-performance liquid chromatography Mark G. Knize*, Cynthia P. Salmon, Ellen C. Hopmans, James S. Felton Biology and Biotechnology Research Program, L-452, Lawrence Livermore National Laboratory,,, Livermore, CA 94550, USA Abstract Carcinogenic and mutagenic heterocyclic aromatic amines (HAA) are natural products often present at ng/g levels in muscle meats when they are cooked at temperatures over 150°C. Using solid-phase extraction and high performance liquid chromatography (HPLC) with photodiode array UV detection, samples were analyzed for the following heterocyclic amines: DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline); IQ (2-amino-3-methylimidazo[4,5-f]quinoline); MeIQx (2- amino-3,8-dimethylimidazo[4,5-f]quinoxaline); and PhIP (2-amino-l-methyl-6-phenylimidazo[4,5-b]pyridine). Quality con- trol samples, analyzed periodically over two years in a blind study, show relative standard deviations ranging from 22 to 38% for the compounds found, variations typical for analysis at ng/g levels. Amounts range from undetectable levels (less than 0.1 ng/g) to hundreds of ng/g of PhIP for frying or grilling at high meat surface temperatures. Beef, chicken, pork and lamb can all have greater than 10 ng/g of PhIE Ground chicken breast meat has lower amounts of heterocyclic amines than intact muscle pieces of the same size cooked identically. Restaurant prepared samples that we analyzed contained undetectable levels up to 14 ng/g total heterocyclic amines for a beef steak sample. Not extracted with the above method are related mutagenic heterocyclic amines, which have been reported in cooked foods in our laboratory and others. Method development using ion exchange on an SCX solid-phase extraction cartridge shows promise in providing a method for the quantitation of these mutagenic dimethyl-, trimethyl- and furo-imidazopyridines where a practical analysis method is needed. Keywords: Food analysis; Aromatic amines, heterocyclic; Amines 1. Introduction The search for carcinogenic agents in foods is directed towards explaining differences in cancer occurrence in humans. Analysis of the health risks of dietary chemicals has focused either on exogenous chemicals added to foods, such as pesticides and artificial sweeteners, or endogenous substances natu- rally present or formed within foods, such as fats and fungal metabolites. The finding that extracts of cooked muscle meats produce a potent response in the Ames~Salmonella mutation test led to studies using analytical chemis- *Corresponding author. try methods to isolate and identify the chemicals responsible for the mutagenic activity. These potent mutagens in bacterial test systems have been shown to be carcinogenic in animal test systems and have been the subject of hundreds of research articles in the last 17 years [1-5]. The formation of mutagenic chemicals in meats has been explained by the condensation of creatine or creatinine with amino acids and sugars or their thermal decomposition products in model systems and meats [6,7]. Many heterocyclic aromatic amines have been isolated and identified from cooked meats or model systems, but four compounds are frequently reported in food surveys [8-12]. These are: DiMeIQx (2- 0021-9673/97/$17.00 Copyright © 1997 Elsevier Science BN. All rights reserved PII S0021-9673(96)00720-0