Chromatographic resolution of molecular species of phosphatidylserines and phosphatidylethanolamines as their N-trifluoroacetyl-O-methyl and N-acetyl-O-methyl derivatives.

A new technique is described for preparing the N-trifluoroacetyl-O-methyl derivatives of phosphatidylserine and phosphatidylethanolamine. It is rapid, and the derivatives are well separated into the following main molecular species by argentation thin-layer chromatography: saturated-monoene, saturated-dienoic, monoene-dienoic, diene-dienoic, saturated-trienoic, saturated-tetraenoic, saturated-pentaenoic and saturated-hexaenoic. The procedure gave full recovery of phosphatidylethanolamine, while phosphatidylserine in addition gave varying amounts of another derivative, probably a cyclic azlactone. The N-acetyl-O-methyl derivatives were therefore also prepared by a similar procedure. These derivatives separated similarly well on argentation chromatography, and both phosphatidylserine and phosphatidylethanolamine gave full recoveries. The two techniques have been used to analyze rat liver phosphatidylserine and phosphatidylethanolamine.