Tentative identification of an unusual naturally-occurring polyenoic fatty acid by calculations from precision open-tubular GLC and structural element retention data

Abstract

The calculation of equivalent chain lengths for polyenoic fatty acids can be effected from fractional chain length values for structural elements obtained on open-tubular columns. Particular attention must be paid to the position of ethylenic bonds and to adjustments dictated by combination of two or more ethylenic bonds. Both an unusual C18 acid with ethylenic bonds in the 3, 6, 9, 12 and 15 positions and the corresponding multiple degradation products from partial hydrazine reduction can be tentatively identified by this technique. Additional confirmation of structures is obtained by “small shifts”, the close comparison of the mixtures of fatty acids on two liquid phases of slightly differing polarity.