Quantitation of 13 Heterocyclic Aromatic Amines in Cooked Beef, Pork, and Chicken by Liquid Chromatography−Electrospray Ionization/Tandem Mass Spectrometry

The concentrations of heterocyclic aromatic amines (HAAs) were determined, by liquid chromatography−electrospray ionization/tandem mass spectrometry (LC-ESI-MS/MS), in 26 samples of beef, pork, and chicken cooked to various levels of doneness. The HAAs identified were 2-amino-3-methylimidazo[4,5-f]quinoline, 2-amino-1-methylimidazo[4,5-b]quinoline, 2-amino-1-methylimidazo[4,5-g]quinoxaline (IgQx), 2-amino-3-methylimidazo[4,5-f]quinoxaline, 2-amino-1,7-dimethylimidazo[4,5-g]quinoxaline (7-MeIgQx), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-1,6-dimethyl-furo[3,2-e]imidazo[4,5-b]pyridine, 2-amino-1,6,7-trimethylimidazo[4,5-g]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, 2-amino-1,7,9-trimethylimidazo[4,5-g]quinoxaline, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-9H-pyrido[2,3-b]indole, and 2-amino-3-methyl-9H-pyrido[2,3-b]indole. The concentrations of these compounds ranged from <0.03 to 305 parts per billion (micrograms per kilogram). PhIP was the most abundant HAA formed in very well done barbecued chicken (up to 305 µg/kg), broiled bacon (16 µg/kg), and pan-fried bacon (4.9 µg/kg). 7-MeIgQx was the most abundant HAA formed in very well done pan-fried beef and steak, and in beef gravy, at concentrations up to 30 µg/kg. Several other linear tricyclic ring HAAs containing the IgQx skeleton are formed at concentrations in cooked meats that are relatively high in comparison to the concentrations of their angular tricyclic ring isomers, the latter of which are known experimental animal carcinogens and potential human carcinogens. The toxicological properties of these recently discovered IgQx derivatives warrant further investigation and assessment.

本研究采用液相色谱-电喷雾电离串联质谱（liquid chromatography−electrospray ionization/tandem mass spectrometry, LC-ESI-MS/MS），对26份不同熟制程度的牛肉、猪肉及鸡肉样本中的杂环芳香胺（heterocyclic aromatic amines, HAAs）含量进行了测定。共鉴定出13种杂环芳香胺，具体包括：2-氨基-3-甲基咪唑并[4,5-f]喹啉（2-amino-3-methylimidazo[4,5-f]quinoline）、2-氨基-1-甲基咪唑并[4,5-b]喹啉（2-amino-1-methylimidazo[4,5-b]quinoline）、2-氨基-1-甲基咪唑并[4,5-g]喹喔啉（2-amino-1-methylimidazo[4,5-g]quinoxaline, IgQx）、2-氨基-3-甲基咪唑并[4,5-f]喹喔啉（2-amino-3-methylimidazo[4,5-f]quinoxaline）、2-氨基-1,7-二甲基咪唑并[4,5-g]喹喔啉（2-amino-1,7-dimethylimidazo[4,5-g]quinoxaline, 7-MeIgQx）、2-氨基-3,8-二甲基咪唑并[4,5-f]喹喔啉（2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline）、2-氨基-1,6-二甲基呋喃并[3,2-e]咪唑并[4,5-b]吡啶（2-amino-1,6-dimethyl-furo[3,2-e]imidazo[4,5-b]pyridine）、2-氨基-1,6,7-三甲基咪唑并[4,5-g]喹喔啉（2-amino-1,6,7-trimethylimidazo[4,5-g]quinoxaline）、2-氨基-3,4,8-三甲基咪唑并[4,5-f]喹喔啉（2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline）、2-氨基-1,7,9-三甲基咪唑并[4,5-g]喹喔啉（2-amino-1,7,9-trimethylimidazo[4,5-g]quinoxaline）、2-氨基-1-甲基-6-苯基咪唑并[4,5-b]吡啶（2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, PhIP）、2-氨基-9H-吡啶并[2,3-b]吲哚（2-amino-9H-pyrido[2,3-b]indole）、2-氨基-3-甲基-9H-吡啶并[2,3-b]吲哚（2-amino-3-methyl-9H-pyrido[2,3-b]indole）。上述化合物的浓度区间为<0.03至305 μg/kg（即十亿分之一浓度单位）。其中，PhIP是全熟烧烤鸡肉（最高可达305 μg/kg）、煎制培根（16 μg/kg）及平底锅煎制培根（4.9 μg/kg）中含量最高的杂环芳香胺；7-MeIgQx则为全熟平底锅煎制牛肉、牛排及牛肉肉汁中含量最高的杂环芳香胺，其最高浓度可达30 μg/kg。另有多种以IgQx骨架为结构的线性三环杂环芳香胺，在熟制肉类中的含量相对高于其角型三环异构体；后者已被证实为实验动物致癌物，并被认为具有潜在人类致癌性。上述新近发现的IgQx衍生物的毒理学特性，有待进一步研究与评估。