A chemical test is a quantitative or qualitative procedure that is used to prove the existence or to assess a chemical compound and or chemical group with the help of a reactant.Various tests exist to chemical test carbohydrate and once carbohydrate is detected, advanced tests could be carried out to categorize and distinguish it from other compounds. 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 which results in the formation of 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. 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. The solution must be heated for three minutes in a boiling water bath and the appearance of a reddish precipitate will give out a positive result for monosaccharides.
Named after the American chemist Stanley Rossiter Benedict,one of the chemical test carbohydrate utilized to detect the existence of reducing sugars is the Benedict’s test.
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 carbohydrates are mainly carried out by researchers to study the various reactions of carbohydrates with the reagents used to classify and identify its compounds.
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