抄録
Reversed phase high performance liquid chromatography (HPLC) with an RI detector was used to separate and determine hydroperoxides of autoxidized ethyl oleate, linoleate and linolenate.
Ethyl oleate hydroperoxide appeared as a single peak apart from unoxidized ethyl oleate on the chromatogram. The hydroperoxide isomers formed by autoxidation of ethyl linoleate were resolved into two components which were geometrical isomers having cis-trans and trans-trans conjugated diene structures. Autoxidized ethyl linolenate gave two peaks of conjugated diene monohydroperoxides and conjugated triene dihydroperoxides, respectively. Under the HPLC conditions used here, the hydroperoxides could be separated according to the number of their double bonds and hydroperoxy groups, and the configuration of the conjugated double bonds (cis-trans and trans-trans), but not on the basis of the difference in the location of hydroperoxy groups.
When autoxidized esters were subjected to HPLC analysis directly, a good linear relationship was observed between the ratio of the peak area of hydroperoxides to that of all peaks on the chromatogram and POV of the sample ester in the range of 303, 000meq/kg. POV determined by this procedure agreed quite well with those measured by the official titration method.
