Effect of Ethyl Alcohol on the Dinitrosalicylic Acid Assay for Reducing SugarsNyla Z. Numan1,2 and John C. Ford3*
- *Corresponding Author:
- John C. Ford
Department of Chemistry, Indiana University of Pennsylvania
Oakland Avenue, Indiana, PA, USA
E-mail: [email protected]
Received date: 06/08/2015; Accepted date: 27/08/2015; Published date: 01/09/2015
The determination of reducing sugars, especially glucose, is of considerable interest. An assay attributed to Miller using 3,5-dinitrosalicyclic acid (DNS) is widely used but suffers from some limitations. It is, nonetheless, convenient and recommended by the IUPAC Commission on Biotechnology for measuring cellulase activity. We found that 5-10% concentrations of methanol, ethanol, 1- and 2-propanol interfered with the DNS assay and gave a positive error (an apparent increase in glucose) when aqueous standards were used for calibrating the assay. For ethanol concentrations beyond about 15%, the assay gave a negative error. In the case of ethanol, this was due to an effect of ethanol on the color-forming reaction as well as a slight effect on the spectral absorbance of the product.