In-Depth Lipidome Annotation Through an Operatively Simple Method Combining Cross-Metathesis Reaction and Tandem Mass Spectrometry

The in-depth knowledge of lipid biological functions calls for a comprehensive lipid structure annotation that implies implementing a method to locate fatty acids unsaturations. To address this challenge we have associated Grubbs' cross metathesis reaction and liquid chromatography hyphenated to tandem mass spectrometry. The pretreatment of lipids containing samples by Grubbs' catalyst and an appropriate alken generates substituted lipids through cross-metathesis reaction under mild, chemoselective and highly reproducible conditions. A systematic LC-MS/MS analysis of the reaction mixture allows locating unambigouslt the double bounds in fatty acid side chains. This method has en successfully applied at a nanomole scale to commerical standard mixtures as well as in lipid extracts from an in vitro model of corneal toxicity.