Abstract 031
The Determination of Ascorbates in Beer by Liquid Chromatography with Electrochemical Detection
J. Amer. Soc. Brew. Chem. 45: 33-37, 1987
E.J. Knudson and K.J. Siebert
A liquid chromatography/electrochemistry technique for detn. of nonoxidized ascorbates was shown to work for beer and other beverages. The method was rapid, very selective and had limit of detection of 0.17 mg/l for (i) ascorbic acid or (ii) isoascorbic acid in aqueous samples and of 0.28 mg/l in beer. Coeff. of variation for ascorbate and isoascorbate were 1.4-3.2% over the range 5-30 mg/l. Effects of storage of canned and bottled beers at 0, 20 and 38°C for less than or equal 30 wk on ascorbate concn. were also examined. Particular ascorbate species used, i.e. (i) or (ii), was established by coinjecting a known standard with the beverage containing the unknown compound, then plotting the 2nd derivative of the chromatogram. This method will distinguish 2 overlapping peaks with resolution as low as 0.5 and peak area ratios as large as 4 or 5:1.
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