Seliwanoff’s Test- Definition, Principle, Procedure, Result, Uses


Seliwanoff’s test is a chemical test that is used to distinguish between two types of sugars: ketoses and aldoses. Ketoses are sugars that have a ketone group (C=O) in their structure, while aldoses are sugars that have an aldehyde group (CHO) in their structure. Examples of ketoses are fructose, ribulose, and xylulose. Examples of aldoses are glucose, ribose, and xylose.

Seliwanoff’s test is based on the fact that ketoses react faster and more intensely with a reagent composed of resorcinol and concentrated hydrochloric acid (HCl) than aldoses. The reagent causes the dehydration of the sugars and the formation of a colored complex called xanthenoid. The color of the complex ranges from pink to cherry red depending on the type and concentration of the sugar. Ketoses produce a deep cherry red color within a minute, while aldoses produce a faint pink color after several minutes.

Seliwanoff’s test can be used to detect the presence of ketohexoses (six-carbon ketoses) in a given sample, such as fructose. It can also be used to differentiate ketoses from aldoses in a mixture of sugars. However, it cannot identify the specific type of ketose or aldose present in the sample. For that purpose, other tests are required.