Separation of alkenylacyl, alkylacyl, and diacyl analogues and their molecular species by high performance liquid chromatography

Abstract

High performance liquid chromatography methods were established for separation of alkenylacyl, alkylacyl, and diacyl acetylglycerols derived from ethanolamine glycerophospholipids (EGP) and for separation of the individual molecular species from each of the separated classes. The EGP were isolated from bovine brain, hydrolyzed with phospholipase C, and acetylated with acetic anhydride. The three classes of diradylacetylglycerols were separated quantitatively on a mu Porasil silica column. Individual classes were further fractionated on a Zorbax ODS reverse phase column. By gas--liquid chromatographic quantitation of each peak, 29-33 different molecular species were identified within each class. For alkenylacyl-GPE, the major species were 18:1-18:1, 21.8%, and 16:0-18:1, 14.8%. Polyenoic fatty acids predominated at the 2-position of diacyl-GPE. The major species were 18:0-22:6 (n-3), 25.5%, and 18:0-20:4 (n-6), 15.8%. Three species of alkylacyl-GPE, 18:0-20:6 (n-3), 16:0-22:4 (n-6), and 18:0-22:4 (n-6), each accounted for 10%.