Solvents for Thin Layer Chromatography of Blood Serum Lipids

Abstract

MIXTURES in several proportions of petroleum ether (boiling point 30°–60° C), diethyl ether and acetic acid have been widely used as solvents for the separation by thin layer chromatography on silica gel plates of lipid extracts of tissue and blood serum. The following solvent proportions have been used: 90 : 10 : 1 (by volume) and 70 : 30 : 2 (ref. 1); 80 : 20 : 1 (ref. 2); 85 : 15 : 1 (ref. 3). This last mixture seems to be extensively used at the present moment⁴. With this mixture phospholipids and diglycerides remain at the bottom of the plates. Cholesterol esters, triglycerides, fatty acids, free cholesterol and diglycerides migrate (cholesterol esters most and diglycerides least); however, with the exception of cholesterol esters, all these compounds remain in the lower half of the plate. The separation on the plate of the fatty acids, free cholesterol and triglycerides is very small, making isolation by scraping difficult. The same is true of diglycerides and phospholipids or cholesterol. We observed experimentally that it is possible to obtain better separations by increasing the proportion of acetic acid in the solvent mixture. The object of this work was to systematize these observations by applying the method to the separation of blood serum lipids.