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Tests for carbohydrates

Tests for Carbohydrates (Preliminary test and Confirmatory test)

Tests For Carbohydrates

Preliminary Tests for Carbohydrates

TestExperimentObservationConclusion/Result
HeatingSlowly heated some original solution in a test tube.No precipitate formationProteins are absent
Iodine Test2-3 drops of original solution and then add a few drops of iodine solution.The solution turns Blue-Black in colorationCarbohydrates are present
Spot Test

 

Poured one or two drops of original solution with the help of a dropper on a filter paper and allowed it to dry.No greasy spot appears on the filter paperLipids are absent

Confirmatory Tests for Carbohydrates

TestExperimentObservationConclusion/Result
Benedict’s Test7 drops of original solution + 2-3 ml of Benedict’s solution + gentle heatingBlue color of the solution changes into green, then yellow to orange at last brick red precipitates are formedCarbohydrates are present
Molisch Test

 

Took 2 ml of O.S. in a test tube. Two drops of the Molisch reagent (a solution of -napthol in 95% ethanol) was added. Then poured slowly into a tube containing two ml of concentrated sulfuric acid so that two layers form.The formation of a purple product at the interface of the two layers.

 

Carbohydrates are confirmed

Prof. Imran Khan

About Muhammad Naveed Iqbal

Muhammad Naveed Iqbal
Lecturer in Botany.PhD (Plant Sciences) Scholar

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