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Analysis of Isomeric Flavor and Aroma Compounds by High Resolution IMS-MS: Application Note

The TOFWERK IMS-TOF enables rapid separation of isomeric compounds even in complex mixtures.

The characteristic aroma and flavor of many of our most beloved drinks – such as beer, whisky and coffee – have strong dependence on the relative concentrations of constituent compounds. These beverages contain a rich array of molecules, many of which exist as isomeric mixtures. Subtle changes in the ratio of such isomers can significantly affect the palatability of a beverage.

Currently, analysis of flavor and aroma compounds is commonly carried out by GC-MS. Even though GC-MS techniques can exhibit high separation power, they lack speed due to sometimes cumbersome sample separation and analysis times of usually more than 30 minutes. The TOFWERK IMS-TOF exhibits comparable separation power but only a fraction of the time is needed. In many cases, beverages can just be diluted in an appropriate solvent and directly injected for analysis (“dilute-and-shoot”), with analyses not taking longer than a couple of minutes.

Here we show examples of such a direct analysis for beer and whisky. In both cases, separation of cis and trans oriented isomers which have strong influence on the taste of these beverages is achieved.

Direct analysis of isomeric compounds found in beer and whiskey using the TOFWERK IMS-TOF. Top: Separation of cis and trans isohumulone in beer. Whereas a cis/trans ratio of 0.4 yields a delightful taste, a beer with almost no trans isohumulone (as found in old or expired beers) will be quite bitter. Bottom: Separation of cis and trans quercus lactone (“whiskey lactone”) in two different whiskey brands. The ratio between the two isomers is known to strongly influence the character of the whiskey.