Quantitative determination of double bond positions in unsaturated fatty acids after oxidative cleavage

The position and amt of unsaturation in fatty acids have been determined, especially in pure fractions of partially hydrogenated fats. In developing a quantitative method for determination of ethylenic bonds in monounsaturated and polyunsaturated fatty acids several procedures were combined. Key features include oxidative cleavage; recovery of cleaved acids as salts; and their conversion to methyl, ethyl or butyl esters for programmed gas‐liquid chromatographic analysis. Monobasic analyses closely agree with the corresponding dibasic analyses, except neither malonic nor propionic acid has been quantitatively estimated. Analyses are shown for cleavage of high purity oleic, linoleic and linolenic acids; forcis andtrans monoenates; and for conjugated and nonconjugated dienoates. Demonstrated are the accuracy, precision and applicability of the procedure to a wide range of pure fractions isolated after both heterogeneous and homogeneous partial catalytic hydrogenation of polyunsaturated fatty acids.