Quantification of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) in beef extracts by liquid chromatography with electrochemical detection (LCEC).

A simple and sensitive method was developed for quantification of mutagenic/carcinogenic aminoimidazoquinoline and aminoimidazoquinoxaline compounds in heated materials. Samples were partially purified by blue-cotton treatment, 0.1 N HCl-methylene dichloride partition and separation in a SEP-PAK silica cartridge. The recoveries of aminoimidazoquinoline and aminoimidazoquinoxaline compounds at the step of partial purification were estimated by spiking with 14C-labeled compounds. The compounds in partially purified materials were analyzed by liquid chromatography with electrochemical detection using a combination of two columns of octadecyl silane and cation exchange. Bacteriological-grade beef extract was found to contain 41.6 and 58.7 ng/g of 2-amino-3-methylimidazo[4,5-f]quinoline and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), respectively. MeIQx was also detected at a level of 3.1 ng per g in food-grade beef extract.