3Test Tube rack Test tube holder Test tube (4 in number) Equipment requiredEach student needs:Test Tube rackTest tube holderTest tube (4 in number)
4MOLISCH’S TEST PROCEDURE Take 2ml of solution in a test tube. Add two drops of Molish’s reagent.Mix it well.Under the cooling conditions incline the test tube and add 2 ml concentrated H2SO4 slowly along the sides of the test tube.Don’t mix the content
5H2SO4 is sulphuric acid.Sulphuric Acid is the most corrosive acid.This reaction is exo-thermic reaction.Acid and Water don’t go well together.Please be CAREFUL!!
6BENEDICT’S TEST PROCEDURE Take 5ml of Benedict’s reagent Add 8 drops of solution to it.Mix well.Boil it for 2 minutes.Cool under tap water.
7Seliwanoff’s Test PROCEDURE Take 3 ml of Seliwanoff’s reagent. Add 3ml of carbohydrate solution.Mix well and heat for 3 minutes.Cool under tap water.
8IODINE TEST PROCEDURE Take 2ml of solution in a test tube. Add 2 drops of iodine solutionMix well
9Molisch's Test Documentation Principle Observation Inference As you get your results start writing your observation in the observation column. The principle and inference will be discussed at the end of the session.Molisch's TestPrincipleObservationInference
10Before You Start Please button up your laboratory coats. Girls tie your hairsCheck the temperature of the water bath. (>90)Cool for no more than half a minute under tap water.
12Principle Of Molisch’s Test General test for carbohydratesMolisch Reagent composition: 5% alcoholic α- napthol.Carbohydrates in the presence of hot mineral acids undergo dehydration forming hydroxy - methyl furfurals.This condenses with α-napthol to form a purple ring at the junction of the two layers.
13Molisch’s test General test for carbohydrates Observation Inference A purple ring is observed at the junction of the two layersIndicates the given solution is a carbohydrate solution
14Content’s of Benedict's reagent Copper sulfate: provide cupric ionsSodium Citrate: Prevents the precipitation of cupric ionsSodium Carbonate: Provides an alkaline medium
15Principle of benedict’s test In an alkaline medium carbohydrates form enediols .Enediols reduce cupric ions to cuprous forming a colored complex.It is called as semi quantitative test which gives an approximate percentage of sugar present in the urine of a diabetic person
16BENEDICT’S TEST Observation Inference Colour of the solution changes from blue to green, yellow, orangeIndicates the presence of a reducing sugar.
17INTERPRETATION OF BENEDICT’S TEST ColourPercentage of sugarGreen0.5 (+)Yellow1.0 (++)Orange1.5 (+++)Red2.0 (++++)
18Importance of the Benedict's Test Used in the preparation of Urostix for diagnosing glucose in urineUsed by Diabetics to check their glucose status.
19Principle of Seliwanoff's test Seliwanoff's Reagent composition: Resorcinol in Concentrated HCLPrinciple:In acidic medium carbohydrates form furfurals which react with resorcinol to give a cherry red colour.
20Seliwanoff's test Observation Inference Cherry red colour is observed Indicates the presence of a ketohexose i.e fructose.
21Principle of Iodine test Principle: Starch a polysaccharide forms a complex with iodine which gives a blue colour.
22IODINE TEST Observation Inference Light blue colour is observed Indicates the presence of starch