Determination of serum lipo-proteins by paper electrophoresis after preliminary staining with Sudan black-B.

UR PRESENT KNOWLEDGE of human serum lipoproteins and their significance in atherosclerosis may be attributed to the development of suitable methods (1, 4, 6, 8, 9, 13, 15) and to extensive studies of human subjects (2, 5, 10, 11, 16, 18) by such methods. The ultracentrifugal, the chemical, or the free electrophoretic methods are technically difficult for routine determinations of serum lipoproteins. Paper electrophoretic methods would appear more applicable for lipoprotein determination; however, several major difficulties have been experienced using existing technics. When staining the lipoproteins after electrophoresis, discoloration of the paper makes a stable base line difficult to obtain. Secondly, the intensity of staining is generally inadequate to give distinct peaks of increased optical density. The dye is unstable and causes the preparation to fade rapidly. Several other objections to paper electrophoretic technics should be considered. Using the conventional methods of staining after migration of the proteins, the staining solution may elute lipid from the lipoproteins. Solubility of dye in the various lipoprotein fractions may be variable, making a direct transposition of staining intensity to chemical quantities difficult. Our described modification of McDonald’s method (15) for the determination of serum lipoproteins by overcoming the enumerated dis-