Determination of structure of unsaturated fatty acids via reductive ozonolysis

An improved method of reductive ozonolysis for the determination of structure of unsaturated fatty acids is reported. The ozonization is carried out at −60–−70C by adding the sample dissolved in pentane to a .02–.03 M pentane solution of ozone. The reduction is effected by the Lindlar catalyst at 0C in pentane or in other solvents, such as the methyl esters of short-chain fatty acids or in dimethyl phthalate, and the aldehydic fragments are analyzed by gas-liquid chromatography (GLC). The method is applied to the structural analyses of methyl esters of oleic, linoleic, linolenic, and arachidonic acids. The sensitivity of the method is demonstrated by the analysis of methyl oleate containing a small amount of added methyl linolenate. Mixtures of methyl oleate and petroselinate are analyzed to demonstrate the identification of the simple aldehydes and ester-aldehydes, and to show the potential of the method for quantitative analysis of mixtures of unsaturated esters. Supported in part by the U.S. Public Health Service, N.I.H. Grant H-5735, and in part by a contract with the U. S. Department of Interior, Fish and Wildlife Service. Presented at the AOCS meeting in Chicago, Ill., 1961.