1-Palmitoyl-2-linoleoyl-phosphatidylethanolamine degrades relatively quickly when subjected to common storage and handling procedures. The degradation products consist of compounds in which double bonds in the sn-2 position acyl chain are partially oxidized and of products arising from the hydrolysis of the acyl ester bonds. Thin-layer chromatography (TLC), which is widely utilized to isolate and to ascertain the purity of phospholipids, does not readily separate the oxidation products from the parent lipid class. High-performance liquid chromatography (HPLC), however, employing a normal phase column and an isocratic, UV-transparent solvent system, can be employed to produce a rapid analytical or preparative of phosphatidylethanolamine (PE) from these degradative impurities.