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2-Acetyl-4-tetrahydroxybutylimidazole and 4-methylimidazole in caramel colours, vinegar and beverages in China

A survey of 2-acetyl-4-tetrahydroxybutylimidazole (THI) and 4-methylimidazole (4-MeI) concentrations in caramel colours, vinegar and beverages from the Chinese market were performed by ultrahigh-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). In total, 117 samples, 78 caramel colour samples, 23 vinegar samples and 16 beverage samples, were investigated. The results indicated that 4-MeI was found in all samples. THI was found in a part of the samples and also the level range was lower compared to 4-MeI. In caramel colour samples, the concentration level range of THI was 1.0–74.3 mg/kg and of 4-MeI was 1.5–1291.8 mg/kg. In vinegar samples, the concentration level range of THI was 13.3–119.2 µg/L and for 4-MeI 111.2–2077.8 µg/L. In beverage samples, THI was only found in two samples and the concentration level range of 4-MeI was 10.8–307.1 µg/L. THI and 4-MeI levels in vinegar and beverages were rather low compared with those in caramel colour samples. These observations can be helpful for evaluating individual exposure to THI and 4-MeI from caramel colours, vinegar and beverages in China.