Chemical Test Carbohydrate

A chemical test is a quantitative or qualitative process that is used to prove the presence or to assess a chemical compound and or chemical group with the help of a reactant.To chemical test carbohydrate, there are a number of tests that can be conducted to determine if a sample contains carbohydrates and if it does, there are further tests that can be carried out to classify and identify it. Chemical test carbohydrate include, The Molisch Test, The Iodine/Potassium Iodide Test, Benedict’s Test, Barfoed’s Test, Seliwanoff’s Test and Bial’s Test.

chemical test carbohydrate

The Molisch’s Test is a sensitive chemical test carbohydrate which was discovered by the Austrian botanist Hans Molisch. Sulfuric acid dehydrates the carbohydrate which results in the formation of an aldehyde which is compressed with two phenol molecules that displays a purple or red colored compound. The sample is combined with a small amount of Molisch’s reagent, which is a-naphthol dissolved in ethanol, in a test tube. A small amount of concentrated sulfuric acid is gradually poured to the mixture along the wall of the test tube without mixing to generate a bottom layer.The appearance of a purple ring at the border between the acid and the test layers indicate a positive reaction.Chemical test carbohydrate will give a rapid positive test result for carbohydrates, monosaccharides while disaccharides and polysaccharides react slower.

The Barfoed’s Test is a chemical test carbohydrate that detects the presence of monosaccharides.Placing one ml of a sample solution in a test tube, 3 ml of Barfoed’s reagent, a solution of acetic acid and acetate cupric solution are added. Heat the solution in a boiling water bath for three minutes and if a formation of a reddish precipitate appears, it tests positive for monosaccharides.

Named after the American chemist Stanley Rossiter Benedict,the Benedict’s test is a chemical test carbohydrate used as a test for the presence of reducing sugars.
Place one ml of the sample solution in a test tube and add 2 ml of Benedict’s reagent which is a solution of sodium citrate and sodium carbonate that is mixed with a solution of copper sulfate.A reddish precipitate should appear within the three minutes if any reducing sugars are present when the solution is heated in a boiling water bath for three minutes.

chemical test carbohydrate

Chemical test carbohydrates are mainly carried out by researchers to study the various reactions of carbohydrates with the reagents used to classify and identify its compounds.