2 amino 3 4 dimethylimidazo 4 5 f quinoline

HCAs standards including, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline (7,8-DiMeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 1-methyl-9H-pyrido[3,4-b]indole (Harman), 9H- Pyrido[4,3-b]indole (Norharman), 3-amino-1,4-Dimethyl-5H-pyrido[3,4-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-1-methyl-6-phenyl-Imidazo[4,5-b]pyridine (PhIP), 2-Amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC) and 2-amino-9H-pyrido[2,3-b]indole (AαC) were obtained from Toronto Research Chemicals (Downsview, ON, Canada). Trans fatty acid methyl ester (FAME) standards including, 9 t-14:1, 9 t-16:1, 6 t-18:1, 9 t-18:1, 11 t-18:1, 9 t,12 t-18:2, 11 t-20:1 and 13 t-22:1 were purchased from Nu-Chek Prep, Inc. (Elysian, MN, USA). The HPLC-grade solvents acetonitrile and methanol were bought from Tedia Co. (Fairfield, OH, USA), while ammonia, ammonium acetate, hydrochloric acid and sodium hydroxide were collected from Sinopharm Chemical Regent Co., Ltd. (Shanghai, China). All reagents and chemicals were chromatographic or analytical grade. A Millipore water purification system was used to collect the deionized water (Millipore Co., Bedford, MA, USA).

Unless otherwise stated, all reagents were HPLC, analytical grade or purchased from Sigma-Aldrich (St. Louis, MO, USA). Sodium hydroxide (NaOH), hydro-chloric acid (HCl), and ammonium hydroxide were analytical grade. Methanol (MeOH), ethyl acetate, formic acid, and acetonitrile were HPLC grade. For the determination of heterocyclic amines (HCAs), reagents from Toronto Research Chemicals (Downsview, Ontario, Canada) were purchased: 2-amino-3-methylimidazo [4,5-f]quinoline (IQ), 2-amino-3-methylimidazo[4,5-f]quinoxaline (IQx), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and 2-amino-3,4,7,8-tetramethylimidazo[4,5-f]quinoxaline (4,7,8-TriMeIQx) were used as internal standard.