SILVER ION HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF ESTERS OF ISOMERIC OCTADECENOIC FATTY-ACIDS WITH SHORT-CHAIN MONOUNSATURATED ALCOHOLS

The retention characteristics of a series of positionally isomeric oct adecenoic acids, derivatized with allyl, butenyl, pentenyl and hexenyl alcohols, were studied by high-performance liquid chromatography on a n ion-exchange column loaded with silver ions. For a given isomer the retention factor, k', increased with the distance of the double bond i n the alcohol moiety from the ester group. The general retention patte rns of butenyl, pentenyl and hexenyl esters were similar to those of m ethyl and phenacyl esters of the same series of isomeric fatty acids. Allyl esters differed in that the effect of double bond position in th e fatty acid backbone on retention was weak. The results support the e arlier suggestion for simultaneous interaction between one silver ion and one double and one electron-donating atom or group, presumed to be oxygen co-ordinating with silver ions through its free electron pairs .