Direct N-Me Aziridination Reaction Enables Pinpointing C=C Bonds in Lipids with Mass Spectrometry

The biological functions of lipids largely depend on their chemical structures. The position of C=C bonds is an essential attribute that determines the structures of unsaturated lipids. Here, we developed a new type of chemical derivatization method for C=C bond using aziridination reaction. This new cyclization method for the C=C bonds in lipids based on the direct N-Me aziridination reaction of olefins using N-methyl-O-tosylhydroxylamine (TsONHCH3) as the aminating reagent. When combined with the tandem MS analysis, this novel activation approach for C=C bonds enables the accurate identification their positions in different kinds of unsaturated lipids. Furthermore, an integrated workflow has been established for comprehensively identifying the C=C bond positional isomers of lipids in complicated biological sample. This work provided a new chemical approach for the structural lipidomics.