BEHAVIOR OF VEGETABLE PHOSPHOLIPIDS IN THIN-LAYER CHROMATOGRAPHY - OPTIMIZATION OF MOBILE PHASE, DETECTION AND DIRECT EVALUATION

By systematic studies using a mobile solvent composition triangle, the optimum chloroform-methanol-water mobile phase for the separation of phospholipids by thin-layer chromatography on 5 × 5 cm silica gel was found. By using acetate buffer (pH 4) instead of water in the mobile phase and by impregnation of the silica gel layer with phosphoric acid it was possible to optimize the separation of phospholipids so that baseline separation was obtained, which is necessary for direct evaluation. Another effect of impregnation with phosphoric acid is the higher stability and intensity given with Dittmer-Lester reagent, which is specific for phosphorus. It reacts with the phosphate group common to all phospholipids so that the same signals were obtained with a measuring wavelength of 720 nm for all phosphatidylcholines of soybean, rape-seed and sunflower seed lecithin. The other phosphilipids (phosphatidylethanolamines, phosphatidylinositols and phosphatidic acids) could be quantified by this procedure. The signal intensity was the same for all phospholipids as the molecular weights are very similar, although the patterns of fatty acids are different. © 1990.