FURTHER-STUDIES OF SATURATED METHYL BRANCHED FATTY-ACIDS OF VERNIX CASEOSA LIPID

Thirty-five monomethyl and 46 dimethyl branched acids were identified in the saturated acids of vernix caseosa lipid [human] with chain lengths ranging from C11-C18, using capillary gas chromatography-mass spectrometry. Many other mono-, di- and trimethyl branched acids were partially identified. All methyl branches were on the even numbered C except for some terminal iso methyl groups. Three types of dimethyl branched acids were found: those with a terminal iso structure, those with a terminal anteiso structure and those with neither iso nor anteiso structures. The 4-methyl branch predominated for all types of branched acids. Equivalent chain length data for di- and trimethyl branched acids were determined on a Pentasil (nonpolar) wall coated capillary column and checked by calculation from monomethyl branched acid data. Mass spectral identification was performed with and without the aid of a data system. A possible mode of formation of these acids is discussed.