Seliwanoff's test

The Seliwanow sample or Seliwanoff sample or resorcinol sample, named after Theodor Seliwanoff, is a chemical proof, can be divided into aldoses or ketoses with the carbs.

Implementation and response

For carrying a sugar solution is acidified with concentrated hydrochloric acid, added an ethanolic resorcinol and heated.

Ketoses column under these conditions quickly from water. Ketohexoses, monosaccharides six carbon atoms, and a keto group, for example, fructose, 5-hydroxymethylfurfural thereby form, the (for example, air, oxygen) with resorcinol and an oxidizing agent reacts to form a colored dye.

Aldoses, monosaccharides with an aldehyde, such as glucose, this reaction does not proceed or will only very slowly.