COLORIMETRIC METHODS FOR DETERMINING SERUM CHOLESTEROL

Abstract

Calorimetric methods have been used by a number of workers for the quantitative determination of cholesterol in human blood.Weston (1) and Schmidt (2) used the Salkowski reaction.Grigaut (3), Autenrieth and Funk (4), Henes (5), Csonka (6)) Bloor ( 7), Gettler and Baker (8), and others used the Liebermann-Burchard reaction.Each author used a different method of extraction.Autenrieth and Funk made fourteen determinntions by their method and found an average of 1.278 mg. of cholesterol per 1 cc. of serum.Henes (5), testing some of the same serum by the Weston-Kent (9) method, found an average of 1.267 mg. per 1 cc.Weston (10) added known quantities of cholesterol to serum and recovered it quantitatively by the Weston-Kent method.Henes in the University of Freiburg used the Weston-Kent method for extraction and the Grigaut method for color determination; Windaus used his digitonin method, and Autenrieth used the Autenrieth-Funk method.The results were almost identical.The experiment here described was undertaken in order to have a basis of comparison for the different methods both of extraction and of color determination.Starting with 100 cc. of human.serum, I divided the quantity into two equal parts and added to one part 50 mg. of pure cholesterol dissolved in ether.The flask containing the serum-ether mixture was gently shaken from time to time until the ether had evaporated.By this method an even distribution of the cholesterol in the serum was obtained.A portion of each of these sera was extracted by each of six methods and each of the twelve resulting extracts