Identification of glycerol& cholesterol
Identification of glycerol
Dunsten's test:
2-3 ml of borax solution + 2 drops of phph. + drops of glycerol to it→pink colour into
colourless .
Benedect's test
:
A few drops of glycerol + 5 ml of Benedect's reagent + boil for 2-3 min.
→ compare the
result with sugar solution.
Dichromate test
:
3 ml of glycerol solution + a few drops of potassium dichromate solution
+ 5 ml of conc. HNO3 + mix well → brown colour into blue colour.
Identification of cholesterol
Preparation of
cholesterol solution :
Add a pinch of cholesterol in 5- 6 ml of chloroform and then divide the
solution in two parts.
Salkawski's
test:
One part of cholesterol solution + 2 ml of conc. H2SO4
((drop by drop)) and mix → a reddish colour. Will be seen in the upper chloroform layer and the
acid lower layer assumes a yellow colour with a green fluorescence.
Liebermann –
Burchard test:
The other part of
cholesterol solution + 1ml of acetic
anhydride + a few drops of conc. H2SO4→ observe the change
in colour solution (violet to blue to green)
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