OnLine Ozonolysis Methods for the Determination of Double Bond Position in Unsaturated Lipids
Modern lipidomics relies heavily on mass spectrometry for the structural characterization and quantification of lipids of biological origins. Structural information is gained by tandem mass spectrometry (MS/MS) whereby lipid ions are fragmented to elucidate lipid class, fatty acid chain length, and degree of unsaturation. Unfortunately, however, in most cases double bond position cannot be assigned based on MS/MS data alone and thus significant structural diversity is hidden from such analyses. For this reason, we have developed two online methods for determining double bond position within unsaturated lipids; ozone electrospray ionization mass spectrometry (OzESI–MS) and ozone-induced dissociation (OzID). Both techniques utilize ozone to cleave C–C double bonds that result in chemically induced fragment ions that locate the position(s) of unsaturation.
Key wordsOzonolysis Double bond position Structural characterization Unsaturated lipids Mass spectrometry OzESI–MS OzID
S.J.B. and T.W.M. acknowledge the financial support of the University of Wollongong and the Australian Research Council (Grants DP0452849 and LP0455472). M.C.T. acknowledges the support of an Australian Postgraduate Award. The authors acknowledge Dr. David Harman for providing details of the LTQ modification. The authors also acknowledge MS Jane Deeley for Providing the human lens spectra and Miss Jessica Nealon for the Preparation of the cow kidney sample.
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