Determination of 4-Methylimidazole and 2-Acetyl-4(5)- tetrahydroxybutylimidazole in Caramel Color and Processed Foods by LC-MS/MS

In this study, the quick HPLC-MS/MS method for the simultaneous separation of 2-acetyl-4(5)-tetrahydrox-ybuthylimidazole (THI) and 4-(5)-methylimidazole (4-MI) in alkaline medium was used for caramel color and processed foods in Korea. After a simple sample pretreatment, 51 4-MI-labeled samples were positive for 4-MI and 2 also contained THI. The concentration of 4-MI was 260.5 ~ 24,499.3 μg/kg in caramel color, less than LOD ~ 1,712.5 μg/kg in sauce, 1,242.3, 5,972.2 μg/kg in balsamic vinegar, 2,118.3 ~ 5,802.4 μg/kg in complex seasoning, 82.7 ~ 5,110.6 μg/kg in curry, and 29.9 ~ 464.4 μg/kg in soft drinks. The recovery rate of 4-MI was 97.1 ~ 111.0% in sauce and 81.9 ~ 110.0% in powder and that of THI was 83.6 ~ 106.4% in sauce and 61.2 ~ 99.4% in powder. Our results concluded a safe amount of 4-MI and THI compared to the limit of Korea additive code but the processed foods do not have a limit of caramel color and 4-MI in Korea. Therefore, research and monitoring of 4-MI and THI is needed for processed foods in Korea.