Estimation of Reducing Sugars by DNSA method

/Estimation of Reducing Sugars by DNSA method
Estimation of Reducing Sugars by DNSA method 2018-06-05T07:49:05+00:00

Estimation of Reducing Sugars by DNSA method

Estimation of Reducing Sugars by DNSA method

Introduction

3,5-Dinitrosalicylic acid (DNSA, IUPAC name 2-hydroxy-3,5-dinitrobenzoic acid) is an aromatic compound that reacts with reducing sugars and other reducing molecules to form 3-amino-5-nitrosalicylic acid, which absorbs light strongly at 540 nm (In case of glucose). This method tests for the presence of free carbonyl group (C=O), the so-called reducing sugars. This involves the oxidation of the aldehyde functional group present in, for example, glucose and the ketone functional group in fructose. Simultaneously, 3,5-dinitrosalicylic acid (DNS) is reduced to 3-amino,5-nitrosalicylic acid under alkaline conditions

Requirements

  1. DNSA
  2. Sodium potassium tartarate
  3. 2 N sodium hydroxide (2N NaOH)
  4. Dinitro salicylic acid (DNSA)
  5. Distilled water
  6. Sample

Procedure

  • Prepare 20 mL of 2N NaOH.
  • Weigh 1 g DNSA and dissolve in 20 mL NaOH with the help of a magnetic stirrer
  • Weigh 30 g of sodium potassium tartarate and dissolve in 50 mL dH2O.
  • Slowly pour sodium potassium tartarate solution in the DNSA and NaOH solution and made the volume up to 100 mL (Note: Wait for the two to mix properly).
  • Decant the contents in a brown bottle. Filter if necessary.

Protocol

  1. Take eight tubes and label them as Blank and 1 to 7.
  2. Make dilutions of glucose standards
  3. Add 3 ml of DNSA reagent to all the eight test tubes. Mix well.
  4. Keep in boiling water bath for 15 minutes.
  5. After cooling to room temperature in a cold water bath, record the absorbance with a spectrophotometer at 540nm.
  6. First, take the absorbance (OD) of Blank and make it zero.
  7. Take the OD of all the tubes (No. 1-7). Wash the cuvettes each time after taking OD.
Go Back to Access Protocol Library
Go Back to Fermentation Protocols

News Updates

An MoU was signed between Orbit Biotech and Govt of Punjab during the Progressive Punjab Invest Summit 2015.
Registrations open for the biotech industrial training program starting April/May/June/July 2018. For registrations contact us at +91. 85 91 87 1105
error: Content is protected !!