Analysis of isomeric forms of oxidized triacylglycerols using ultra-high-performance liquid chromatography and tandem mass spectrometry.

Detailed studies on the regioisomeric structures of oxidized species of triacylglycerols (TAG), formed in food during storage and processing, have not been published thus far. In this study, an analytical approach based on efficient ultra-high-performance liquid chromatographic (UHPLC) separation of different isomers of oxidized TAG species and their tandem mass spectrometric analysis was created. A linear solvent gradient based on acetonitrile and acetone was used in the UHPLC method. A novel method utilizing positive ion ESI using ammonia supplemented in the nebulizer gas was used to produce ammonium adduct ions for mass spectrometric analysis. With the UHPLC method used, different regioisomers of TAG species containing oxidized linoleic or oleic acid could be efficiently resolved. Differences in the fragmentation patterns of many of the oxidized TAG isomers could be demonstrated by the tandem mass spectrometric method. On the basis of the results, the approach enables regiospecific analysis of oxidized TAG molecules.