ISOLATION AND QUANTIFICATION OF POLYMERS FROM AUTOXIDIZED FISH OILS BY HIGH-PERFORMANCE SIZE-EXCLUSION CHROMATOGRAPHY WITH AN EVAPORATIVE MASS DETECTOR

Triacylglycerol polymers from autoxidized fish oils were isolated and quantified by size-exclusion chromatography with an evaporative mass detector. Optimum chromatographic conditions were obtained using dichloromethane as the mobile phase and three styrene-divinylbenzene columns coupled in series. The results showed a lack of correlation between polymer content and standard methods for oxidative rancidity assessment. The polymer content was ca. 1% in the starting oils, but the value rapidly increased during autoxidation. Depending on the level of oxidation, a mixture of dimer, trimer and higher polymeric triacylglycerols are formed, the dimers predominating when the total polymer content is less than 10%.