LESSON 1 QUALITATIVE TEST FOR CARBOHYDRATES PDF

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BIOCHEMISTRY LESSON 1 QUALITATIVE TEST FOR CARBOHYDRATES MOLISCH'S TEST, SELIWANOFF, GENERAL, QUATITATIVE TEST FOR CARBOHYDRATE...

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BIOCHEMISTRY LABORATORY

COLLEGE OF ALLIED HEALTH – BSMT

QUALITATIVE TEST FOR CARBOHYDRATES

WEEK 1

TRANSCRIBED BY: AARON JOHN L. TAHANLANGIT 2ND YEAR – MED201

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MATERIALS Test tubes Droppers Graduated cylinders Test tube rack Markers and tape Main Reagents: ✓ Fehling’s A & B ✓ Benedict’s ✓ Seliwanoff’s ✓ Molisch’s ✓ Barfoed’s ✓ Iodine Solution Carbohydrates Solutions: ✓ Glucose ✓ Fructose ✓ Lactose ✓ Sucrose ✓ Starch

1st TEST: MOLISCH’S TEST The Molisch’s Test is considered as the General test for Carbohydrates. Concentrated Sulfuric acid is also used in this test. 1. 2ml of each carbohydrate solutions will be used in 4-test tube. 2. 10 drops of Molisch reagent to each carbohydrate sample. 3. Mix thoroughly. 4. Carefully add 15 to 20 drops of Concentrated Sulfuric Acid (DO NOT STIR). 5. Observe the Color. Glucose

Fructose

Lactose

3RD TEST: FEHLING’S TEST Reduction test to determine the presence of reducing sugars, it differs from benedict’s test due to Fehling’s reagent contains Rochelle salt or sodium potassium tartrate in place of sodium citrate. The Fehling’s solution consists of Solution A and Solution B 1. Each test tube mix 1ml of Fehling’s solution A and 1ml Fehling’s solution B then add 3ml of water 2. The 4-test tubes are placed in boiling water bath for 1 minute, if the solution remain blue, we can add 8 drops of each of the sugar solution to each of the test tubes. 3. Boil again the 4-test tubes for another minutes Glucose

Fructose

2ND TEST: BENEDICT’s TEST Considered for Reducing sugars. 1. 2ml of Benedict’s solution will be used for each 4 empty test tubes. 2. Place to a hot water bath for 30 seconds. If the solution remains the same color of blue (not contaminated) we can proceed. 3. Allow the test tubes to cool down. 4. Add 5 drops of Carbohydrates solutions. 5. Place the 4-test tube to boiling water bath for 2 minutes 6. Cool and observe what will happen. Fructose

Lactose

Sucrose

Sucrose

Small amount of brick red precipitate

Small amount of brick red precipitate

Glucose

Lactose

Sucrose

4TH TEST: BARFOED’S TEST Distinguishes reducing Monosaccharides from reducing disaccharides by controlling ph and time of heating, it also a copper reduction test in acidic conditions 1. In each of the 4-test tube add 2ml of barfoed’s reagent 2. each test tube adds 10 drops of each sugar solution 3. Place the test tubes in boiling water bath for 5 minutes 4. Let it cool Glucose

Fructose

Lactose

Sucrose

BIOCHEMISTRY LABORATORY

COLLEGE OF ALLIED HEALTH – BSMT

QUALITATIVE TEST FOR CARBOHYDRATES TRANSCRIBED BY: AARON JOHN L. TAHANLANGIT 2ND YEAR – MED201

5TH TEST: SELIWANOFF’S TEST Distinguishes between fructose and glucose, overheating of the solution should be avoided. 1. Add 2ml of sugar solutions and 3ml of Seliwanoff’s reagent each test tubes. 2. Boiling water bath for the 1st ten minutes Glucose

1. 2.

Fructose

Lactose

Sucrose

IODINE TEST FOR STARCH Place 2ml of plant starch solution in the test tube, then add a drop of iodine solution Heat the solution.

WEEK 1...