Some Interferences in the Alkaline Copper Method of Reducing Sugar Analysis

It has been found that boric acid and chloride ions suppress the reducing power of glucose and maltose. While boric acid does not affect the linearity of absorbance versus concentration curves, nonlinearities may occur if chloride is present in the solution to be analyzed. It has also been found that the proper upper limit of the alkaline copper method is 175 µg/ml for glucose, as opposed to the commonly adopted value of 300 µg/ml. Copyright © 1984 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim