Chemical Test Carbohydrate
The qualitative or quantitative technique which is implemented to detect the existence or to evaluate a chemical compound and or chemical group by using a reactant is a chemical test.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 desiccates the carbohydrate to produce 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 signal 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 can be used to identify the existence of monosaccharides in the sample.One ml of the sample solution must be added together with 3 ml of Barfoed’s reagent, an acetic acid solution and a solution of acetetate cupric. 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.
Discovered by 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.
One ml of the sample solution should be placed in a test tube with a 2 ml solution of the Benedict’s reagent which contains sodium citrate and sodium carbonate mixed with a copper sulfate solution.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.
Primarily, researchers perform chemical test carbohydrates to examine the different reactions of carbohydrates with the reagents to categorize and detect its compounds.
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