Resolution of molecular species of intact serine and ethanolamine phosphatides by argentation chromatography of their trifluoroacetamides.

An effective resolution of intact phosphatidylserines on the basis of unsaturation has been achieved by conventional argentation thin layer chromatography (TLC) following trifluoracetylaction. The trifluoroacetamides are prepared by treatment with trifluoroacetic anhydride or N-methyl-bis-trifluoroacetamide. The acetamides are resolved with chloroform-methanol-water (65:25:4, v/v/v) on Silica Gel G containing 20% silver nitrate. Subfractions with 0-6 double bonds per molecule were obtained for the phosphatidylserines of pig and ox brain, pig erythrocytes, rat liver, and rabbit skeletal muscle. The preparation of trifluoroacetamides is also advantageous for the silver ion fractionation of phosphatidylethanolamines. The method is applicable to metabolic studies of molecular species using radioactive precursors of neutral lipids, phosphorus, and nitrogenous bases.