Densitometric Determination of C-18 Fatty Acids as Phenacyl Esters Following Reversed-Phase Thin Layer Chromatography

A simple method of quantitatively determining C-18 fatty acids in an aqueous oxidized polyethylene emulsion is presented, utilizing the formation of phenacyl esters in the presence of crown ether as catalyst, followed by separation by reversed-phase thin layer chromatography, and subsequent densitometry of the strongly ultraviolet absorbing separated compounds. The method has good sensitivity, permitting the detection of as little as 5 nanomoles or less of fatty acids, and is applicable to various biological mixtures and to acids of different chain lengths.