Effect of high room-temperature on estimation of blood cholesterol by Bloor's method.

A CCORDING TO BLOOR ‘S METHOD of blood cholesterol determination, the fluid is extracted with a known volume of a 1:3 ether-alcohol mixture, ifitered, an aliquot of the filtrate evaporated, and the Liebermann-Burchard color reaction performed on the residue. The procedure does not allow for loss of solvent by evaporation during filtration. As this loss may be appreciable in tropical climates, it was considered necessary to investigate its effect on the determination. Determination of the cholesterol content in the same specimens of whole blood was carried out in duplicate at 37#{176}, with the use of 0.4 nil, of fluid for 25 ml. of solvent in each instance. The volume was made up accurately before ifitration in the first determination, and after ifitration in the second. Ten milliliters of each filtrate was evaporated to dryness, and the residue was dissolved in 5 ml. of chloroform and treated with a mixture of 2 ml. of acetic anhydride and 0.2 ml. of concentrated sulfuric acid at 20-25#{176} in the dark for 10 min., after which a reading was taken in a Klett-Summerson photoelectric colorimeter equipped with the red filter. The result obtained by using a standard solution of cholesterol in chloroform was expressed in milligrams per 100 ml. for whole blood. Analysis of the data in Table 1 shows clearly that the result of the first determination was significantly higher than that of the second,