Selasa, 21 Februari 2023

Barfoed's Test to Differentiate Between Mono and Disaccharide Reduction

This test is performed to differentiate between mono- and disaccharide reduction. Monosaccharides are more reactive reducing agents than disaccharides and thus react in about 1-2 minutes, while it takes 7-12 minutes for the reducing disaccharides to get hydrolysed and then react in the acidic solution. Therefore it is possible to detect the difference in property reductions.

Barfoed test reaction


Barfoed's reagent:

66.5 g of Cupric acetate dissolved in approximately 900 mL DW. Add 9 mL of Glacial Acetic Acid and boil. Cool and use DW to cool the volume to 1 L and filter if necessary.


  • Take 2- solution: Keep the test tubes for only 1-2 min in a boiling water bath.
  • Then allow a while for the tubes to cool down.
  • Thin red precipitates indicate the presence of a reduction of monosaccharide at the bottom or sides of the tube.


The boiling should not be prolonged beyond 1-2min, otherwise the disaccharide reduction will respond to this test as well.

This test is not effective in detecting urine sugar reduction due to the presence of chloride ions.

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