The body uses cholesterol to make vitamin D and various hormones, such as estrogen, testosterone, and cortical. The body can produce all the cholesterol that it is needs, but it also obtains cholesterol from food. Lieberman-Bernhard test: The Lieberman-Bernhard or acetic anhydride test is used for the determination of cholesterol. The formation of a green or green- blue color after a few minutes is positive.
Lieberman-Bernhard is a reagent used in a colorimetric test to detect cholesterol, which gives a deep green color. This color begins as a purplish, pink color and progresses through to a light green then very dark green color. The color is due to the hydroxyl group -B) of cholesterol reacting with the reagents and increasing the conjugation of the inaugurations in the adjacent fused ring. Because this test uses acetic anhydride and sulfuric acid as reagents caution must be exercised so as not to receive severe burns.
In this experiment, two clean and dry test tubes were prepared with test tube 1 containing dissolved Residue C in methyl chloride and test tube 2 with 1. 0 ml vegetable oil. 5 drops of acetic anhydride was added, followed by 3 drops of concentrated sulfuric acid into both test tubes and were mixed thoroughly. Principle: Oxidation. This test is used in the estimation of blood cholesterol. Cholesterol produces a characteristic green color when it is mixed with the Liebermann-Bernhard reagent, a mixture of acetic anhydride and sulfuric acid.
The change in color may be gradual, initially pink, then blue-purple, and finally deep green. Purpose: -To react with the CA Hydroxyl group of the cholesterol -Used as a colorimetric test to detect cholesterol Equation: Compound responsible for green color: Due to the hydroxyl group (-AH) of cholesterol reacting with the reagents (acetic anhydride and concentrated lobular acid) and increasing the conjugation of the inaugurations in the adjacent fused ring.