Selivanov rehearsal

Positive Selivanov sample

The Seliwanow sample or Seliwanoff sample or also resorcinol sample, named after Theodor Seliwanoff (1859–1938), is a chemical proof with which carbohydrates can be differentiated into ketoses or aldoses .

Execution and response

To do this, a sugar solution is acidified with concentrated hydrochloric acid, an ethanolic resorcinol solution is added and heated.

Ketoses quickly split water under these conditions. Ketohexoses , d. H. Monosaccharides with six carbon atoms and one keto group, e.g. B. fructose , thereby forming 5-hydroxymethylfurfural , which with resorcinol and an oxidizing agent such. B. atmospheric oxygen, reacts to a reddish dye .

Aldoses on the other hand, d. H. Monosaccharides with an aldehyde group , e.g. B. glucose , this reaction does not go into or only very slowly after prolonged heating.

See also

• Bial sample
• Dische rehearsal
• Molisch sample
• Fehling's trial
• Great test

Individual evidence

1. ↑ Theodor Seliwanoff: "Note on a fruit sugar reaction". In: Reports of the German Chemical Society , 20  (1), 1887, pp. 181-182, doi : 10.1002 / cber.18870200144 .
2. ↑ Ulrich Flörke, Robert Wolff: Course topics chemistry. Bonn 1982, ISBN 3-427-43121-5 . Pp. 6 / 7-8.
3. ^ Otto-Albrecht Neumüller (editor): Römpps Chemie Lexikon , 8th edition, Frank'sche Verlagshandlung, Stuttgart 1983, ISBN 3-440-04513-7 , p. 3799.