1. 1 IUG, 2013 Dr. Tarek M. Zaida

2. Isolation of Cholesterol 2

3. Background 3 Definition a waxy substance found in all of the body cells Function - Forms Cell membranes - insulates nerve fibers. - formation of sex hormones - Production of bile salts Synthesis Mostly in liver

4. good & bad cholesterol Cholesterol LDL (bad) HDL (good) 4

5. Isolation of Cholesterol from egg yolk 5 Hen eggEgg whiteAlbuminEgg yolk Lipids + glycoproteins

6. Egg yolk 5% Cholesterol 28% phospholipids 66% glycerides 6

7. Experiment  Reagents and instruments  A hard boiled hen egg  Acetone, Ice, Water bath, Erlenmeyer flask, Funnel, Filter paper, 250 ml beaker 7

8. Reagents and instruments  A hard boiled hen egg  Acetone,  Ice,  Water bath,  Erlenmeyer flask,  Funnel,  Filter paper,  250 ml beaker 8

9. 1. Extraction 1. Peal the hard boiled egg and remove the egg white. 2.In a 250 ml beaker weigh a ½ egg yolk and mash it. 3. To the mashed egg yolk add a 25 ml of acetone and keep stirring for 5 min. 4. Allow the solid to settle and carefully remove the acetone (the above liquid phase) and transfer it to a clean 100 ml Erlenmeyer flask and cover it tightly. 5. To the remained solid phase add a new 25 ml of acetone and repeat step 4. Now you have collected twice the 25 ml of acetone extract (it contains the cholesterol). 9

10. 2. Isolation & Purification 1. Using a funnel and a filter paper, filter the 50 ml of acetone extract into a clean 100 ml beaker. 2.Evaporate the acetone by placing the beaker on the steam bath in the hood until about 10 ml of extract is left. 3.Cover the warm acetone extract and immediately transfer it on ice and let it stand for 20 min. A white precipitate will form (this is the crude cholesterol). Remove the flask from ice. Get rid of the liquid phase. 10

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