Answer to Question #248679 in Biochemistry for jan

Question

 Liebermann-Burchard test. Explain the importance of each reagent used in this test.

Answer 1

THE Liebermann–Burchard reaction for steroids1, which consists in adding a few drops of acetic anhydride and concentrated sulphuric acid to the chloroform solution of the sterol, is not only used as a qualitative test for it but also for its quantitative estimation in blood, etc. Formation of coloured halochromic sulphate of ketone was suggested by Wieland and Weil2 in explaining this reaction. The reaction product, when poured into water, was found to be soluble in the latter, and the grass-green coloration was observed. By studying this water-soluble colouring product, it has been possible for us to state definitely that it is the sulphonic acid derivative of cholesterilene, which has previously been reported to be formed through the action of sulphuric acid on cholesterol dissolved in glacial acetic acid3. The acid gives insoluble calcium and barium salts.