Determination of vanillin and related flavor compounds in cocoa drink by capillary electrophoresis

A simple, rapid, and reliable capillary electrophoresis (CE) method using a photodiode array detector determined four flavor components (vanillin, ethylvanillin, 2-methoxyphenol, and 2-ethoxyphenol) in cocoa drink. Simple and rapid sample preparation required only dilution. Separation used 50 mM phosphate buffer and 2 mM cetyltrimethylammonium hydroxide (CTAH) at pH 10 with 10% acetonitrile. Sorbic acid was the internal standard (I.S.). Vanillin and related compounds were determined in 7 min, with the limits of detection at 1.6 μg/ml with S/N > 3 and a quantitation range of 5–500 μg/ml. Recoveries were investigated in cocoa drink samples with four flavor components. Mean recoveries were 96.3–103.8%. Using this method, the four flavor components were determined from cocoa drink, in which vanillin and ethylvanillin were originally contained as a flavoring and into which Bacillus firmus was added.