High-performance liquid chromatographic analysis of egg yolk phospholipids

A rapid and efficient method for the separation of egg yolk phospholipids by normal-phase high-performance liquid chromatography has been developed. The separation is accomplished on an Ultrasil-NH2 column using hexane, isopropanol, methanol and water mixtures with direct ultraviolet detection at 206 nm. Phospholipids from a methanol extract of fresh lyophilized egg yolks were analyzed providing complete separation of (in order of elution) neutral lipids, phosphatidylcholine, sphingomyelin, lysophosphatidylcholine and phosphatidylethanolamine. Identification of eluting species was accomplished by comparative retention times of standard samples by thin-layer chromatographic analyses of collected fractions. Furthermore, a mixture of naturally occurring phospholipid standards from bovine and egg sources has been separated by this method. In addition to separating the individual classes of phospholipids, in some instances, separation of molecular species within a class was achieved as in the case of cerebrosides, sphingomyelin and partially with phosphatidylethanolamine.