The separation of complex lipide mixtures by the use of silicic acid chromatography.

It is now well established that the various lipide classes of blood (1)) liver (2)) and other organs are metabolically dissimilar. The different fatty acids of the diet (3) and within the organism (4) also have been shown to have variable functions and effects. Methods have recently become available for the rapid and precise analysis of these fatty acids (5) and it is reasonable to expect that an analysis of the fat,ty acid composition of each lipide class will yield rich information concerning the transport and metabolism of fatty acids. Considerations of this type indicate the need for a reliable, standardized method for the separation of the lipide classes. The present communication describes a method for such separation based on adsorption chromatography with silicic acid. Since Trappe’s introduction of silicic acid chromatography for lipide separation in 1940 (6, 7), a considerable experience has been gained with this procedure (8-11). Such information has been put to practical use in many types of lipide separations (1, 12, 13) but workers have found that the separations can be capricious and unreliable. Therefore, a systematic study of the many variables seemed desirable. Information obtained from this study and from previous investigations of the properties of silicic acid (14-16) were used to elaborate a standardized method for the separation of lipide groups. The present report is a description of the method and some representative results.