Ion Mobility–Mass Spectrometry for Lipid Analysis
Ion mobility (IM) is a post ionization tool that can be used to separate lipid ions in the gas phase according to their charge, shape and size. IM can be combined with mass spectrometry (MS), adding three main benefits to traditional approaches for lipid analysis. First, IM allows determination of the collision cross section of a lipid molecule, a physicochemical property related to the conformational structure, which facilitates lipid identification. Second, IM improves the peak capacity and the signal-to-noise ratio, allowing the separation of interfering isobaric lipid species. Third, IM allows a new set of hybrid fragmentation experiments that combine collision-induced dissociation with gas phase separation, improving the specificity of the tandem MS-based approaches. Here, we review the current applications of IM-MS for lipid analysis.