Silver ion HPLC of p-methoxyphenacyl derivatives of unsaturated fatty acids. II. Chain length vs. double bond position

The role of the chain-length and double bond position for the separation of positionally isomeric unsaturated fatty acid p-methoxyphenacyl esters by s ilver ion HPLC was evaluated. A clear effect of chain-length on retention w as found, with k'' decreasing when the number of carbon atoms in the chain increased. Thus, the resolution was affected both by the chain length and d ouble bond position with the double bond position having the major impact. This allowed for the resolution of complex mixtures of fatty acids that dif fer in chain length and position of the double bonds by a single chromatogr aphic run. Examples of such separation on model mixtures are presented.