MOLISCH’S REACTION general reaction for the detection of carbohydrates.
Sugars on reaction with dehydrating agents like strongly concentrated acids (Concentrated H2SO4) yield furfural and furfural derivatives such as hydroxymethyl furfural, which condense With α-naphthol and give a reddish Violet ring.
ii- Ethyl alcohol
2. Concentrated H2SO4
3. Original solution (O.S)- containing a carbohydrate.
- To 2ml of sugar solution (original solution) add 2 to 3 drops of Molisch’s reagent.
- Mix thoroughly.
- Carefully pour 5 ml concentrated H2SO4 along the side of the test tube.
- Acid being heavier will form a layer beneath the sugar solution.
The formation of a reddish violet ring at the junction of the two liquids indicates the presence of carbohydrates.
Carbohydrates are present.
This test is very sensitive and is given by all the carbohydrates
- Wash the apparatus before and after the experiment.
- Carefully pour the acids along the side of the test tube.