An improved rapid thin-layer chromatographic-gas-liquid chromatographic procedure for the determination of free fatty acids in plasma.

Free fatty acids contained in Dole extracts were separated from other lipid components by either a thin layer chromatographic procedure or by a solvent partitioning system. Subsequent gas-liquid chromatographic analysis of methyl esters prepared from fatty acids purified by these two procedures, showed that when fatty acid standards were subjected to these two procedures, comparable recoveries of fatty acids were obtained. When, however, phospholipids and neutral lipids were present in the extracts, the solvent partitioning system yielded 10 to 46% higher values than recorded with the thin layer chromatographic procedure. Compositional data indicated that the higher values measured by the solvent partitioning procedure were probably derived from hydrolysis of other lipid components during the sodium hydroxide step. Purification of fatty acids by the described thin layer chromatographic procedure eliminates this problem and rapidly yields accurate and reliable results.