Resolution of Positional Isomers of Bacterial Long Chain Cyclopropane-ring Containing Fatty Acids by Capillary Column Chromatography

The initial separation of esterified positional isomers of bacterial long chain cyclopropane-ring containing fatty acids by capillary column gas chromatography has been achieved. Lactobacillic (cis-11,12-methyleneoctadecanoic) and dihydrosterculic (cis-9,10-methyleneoctadecanoic), two “C19” acids and cis-9,10-methylenehexadecanoic (“C17”) acid served as standards and were either organically synthesized or prepared from a biological source. The application of this technique for the separation and identification of such acids from a biological source is illustrated. The need of a method for determining the position of the “ring” in these type acids, directly and without degradative procedures, when present in minute sample sizes is discussed.