Assessment of 4-(5-)methylimidazole in soft drinks and dark beer

A B S T R A C T A faster and more robust version of a previously developed method based on ion-pair extraction, acylation with isobutylchloroformate and gas chromatography–mass spectrometry (GC–MS) analysis for determination of 4-(5-)methylimidazole (4-MeI) in soft drinks and dark beer is proposed. The performance of the method was evaluated in terms of linearity (r always > 0.998); recovery (90–101%, 3 levels); and precision (3–8%, 3 levels, n = 6). Limits of detection and quantification in the matrices studied were 0.60 mg/L and 2.2 mg/L, respectively. The optimized method was applied to a wide variety of soft drinks (brand name and generic colas, uncarbonated flavor and energy drinks) and dark beers (lager, ales trappist, ales-stout, weissbier). Overall, soft drinks presented higher amounts of 4-MeI (ranging from 37 to 613 mg/L) than those found in the dark beers (ranging from 3 to 424 mg/L), with colas presenting the highest levels. When the different colas analyzed were compared, the 4-MeI levels in generic colas were generally higher than those in brand-name colas. 4-MeI was found in only one of eight energy drinks studied. Based on available consumption patterns, consumer exposure to the maximum 4MeI given by the soft drinks was 2.3 and 5.7 mg/kg body weight/day, in Europe and the United States, respectively.