An assay for 2‐amino‐3,8‐dimethylimidazo[4,5‐ƒ]‐quinoxaline and 2‐amino‐3,4,8‐trimethylimidazo‐[4,5‐ƒ]quinoxaline in fried beef using capillary column gas chromatography electron capture negative Ion chemical ionization mass spectrometry

A gas chromatographic/mass spectormetric assay has been developed for the simultaneous measurement of 2‐amino‐3,8‐dimethylimidazo[4,5‐ƒ]quinoxaline (MeIQx) and 2‐amino‐3,4,8‐trimethylimidazo[4,5‐ƒ]quinoxaline (DiMeIQx) in fried beef. The method employs capillary column gas chromatography, electron capture negative ion chemical ionization mass spectrometry and a stable isotope labelled analogue of MeIQx as common internal standard. Two patties of lean minced beef which had been cooked separately were analysed and found to contain both compounds (patty 1:2.4 ng MeIQx g −1 meat, 1.2 ng DiMeIQx g −1 meat; patty 2: 1.3 ng MeIQx g −1 meat, 0.5 ng DiMeIQx g −1 meat). Neither compound was present in the meat prior to cooking.