Caramel color is a type of food additive that is used in a variety of food products to give those products a brown coloration. Caramel color is manufactured by heating saccharides such as sugar or glucose, but it also contains 4-methylimidazole as a byproduct formed in the manufacturing process. Animal experiments carried out by the National Toxicology Program (NTP) in the United States have revealed that 4-methylimidazole is highly carcinogenic, and based on that result, the International Agency for Research on Cancer (IARC) has classified the compound as a carcinogenic hazard in an IARC Monograph.(1) Against this backdrop, the EU and United States have established regulations on the allowable content of 4-methylimidazole in caramel color, and the State of California has set a limit on its daily intake.(2)
In this article, we introduce an example of an analysis of 4-methylimidazole in cola by using the Shimadzu Nexera-i™ MT. K. Nakajima
Analysis of 4-Methylimidazole by Using HPLC Flow Line of Nexera-i MT
Table 1 shows the analytical conditions. Fig. 2 shows the chromatogram obtained by an analysis under these conditions using samples prepared by adding 50 μg/L of 4-methylimidazole to a cola stock solution. It was found that the elution peak of 4-methylimidazole could be analyzed under these conditions in Table 1 with no effect of impurities contained in the cola.
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