Quantitative determination of alk‐1‐enyl‐ and alkyl‐glyceryl ethers in neutral lipids and phospholipids

Abstract

A quantitative method for the simultaneous determination of alk-l-enyl- and alkyl-glyceryl ethers is described. Complete hydrogenolysis of carboxylate and phosphate esters of neutral lipids and phospholipids was achieved with lithium aluminum hydride. The hydrogenolysis products of the glyceryl ether containing lipids, alk-l-enyl- and alkyl-glyceryl ethers and alcohols, were identified by thin-layer chromatography (TLC), gas-liquid chromatography (GLC), and infrared spectroscopy. The alk-l-enyl- and alkyl-glyceryl ethers were quantitated by TLC photodensitometry. The specificity of this method can also be extended when used in conjunction with GLC, ion-complexing TLC, zonal scanning, and autoradiography to study composition, isomeric form, and the biosynthesis of glyceryl ethers in neutral and phospholipids.The percentage of alk-l-enyl- and alkyl-glyceryl ethers in bothtthe neutral lipids and phospholipids of various rat tissues was determined by the described method. Glyceryl ether glycerides represent 0.3-1.2% of the total neutral lipids whereas the glyceryl ether phosphatides of brain, heart, marrow, muscle, and spleen represent 4.5-12.0% of their total phospholipids. Higher concentrations of glyceryl alkyl than of alk-l-enyl ethers were found in the neutral lipids whereas the glyceryl alk-l-enyl ethers were found to predominate in the phospholipids.