Method for Determination of Citric and Lactic Acids in Dairy Products

Abstract

A column chromatographic method for the determination of citric and lactic acids has been developed. The column was three-sectioned and was composed of unbuffered H2SO4 and silicic acid. The eluate was collected in three portions of varied size; lactic acid was the only hydroxy acid in the first eluate portion and citric acid was the only acid in the third portion. Citric acid was directly titrated and lactic acid was determined by the use of the FeCl3-HCl-hydroxyorganic acid color reaction. Citric acid concentrations of 0.10 mg. to 0.4 g. per column were determined, with recoveries of 97 to 100%, with an average of 99.18 and a coefficient of variation of 0.47%. Lactic acid concentrations of 50 to 200 µg/5 ml. of eluate were analyzed with accuracies of 94.5 to 100.7%, with an average of 98.6 and a coefficient of variation of 1.2%. Advantages of this procedure are accuracy, low-cost apparatus, simplicity, and a minimum of sample preparation. © 1961, American Dairy Science Association. All rights reserved.