A chemical test is a quantitative or qualitative procedure that is intended to prove the existence or to measure 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. The Molisch Test, The Iodine/Potassium Iodide Test, Benedict’s Test, Barfoed’s Test, Seliwanoff’s Test and Bial’s Test are chemical test carbohydrate.

Named after Austrian botanist Hans Molisch, the Molisch’s Test is a sensitive chemical test carbohydrate. Sulfuric acid dehydrates the carbohydrate to produce an aldehyde which is compressed with two molecules of phenol that results in 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. After it has been mixed, concentrated sulfuric acid, a small amount, is slowly added along the sides of the test tube without mixing to form a bottom layer. If a purple ring appears at the cross point between the acid and the test layers, a positive reaction is indicated. 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. Once the solution is heated in a boiling water bath for three minutes, a reddish precipitate should form within three minutes if it tests positive.

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