Liebermann-Burchard test?

Question

Can the liebermann-burchard test be used to detect cholesterol on pre-packed foods and commercial products? How? Do we follow the same procedure of adding anhydrous choloroform, acetic anhydride and concentrated sulfuric acid to a sample in a dry test tube? Pls answer asap... Badly needed...

Answer 1

Liebermann-Burchard test

A colourimetric test for unsaturated sterols, notably cholesterol; a blue-green colour develops when such substances are added to acetic anhydride and sulfuric acid in chloroform.



For the Liebermann-Burchard test for cholesterol, students put 10 drops of the above solutions of cholesterol, coconut oil, or lard in separate dry test tubes and add 3 drops of acetic anhydride and one drop of concentrated sulfuric acid. Formation of a green or green-blue color after a few minutes is positive. Ideally, the cholesterol solution gives a nice reaction, the coconut oil should show no significant color change, and the lard gives a weak reaction. The results for this test have been variable over the past few years. For example, coconut oil sometimes gives a green color, and unsaturated oils invariably do, whereas lard often gives a brown color. I think the variabilities have been due to using old solutions; they should be made fresh with reasonably fresh samples, which is fairly inconvenient.

Answer 2

From what I have read, the specific chomophore responsible for the color hasn't been identified.