An Untargeted Lipidomics\nWorkflow Incorporating High-Resolution\nDemultiplexing (HRdm) Drift Tube Ion Mobility-Mass Spectrometry

Global discovery lipidomics can provide comprehensive\nchemical\ninformation toward understanding the intricacies of metabolic lipid\ndisorders such as dyslipidemia; however, the isomeric complexity of\nlipid species remains an analytical challenge. Orthogonal separation\nstrategies, such as ion mobility (IM), can be inserted into liquid\nchromatography-mass spectrometry (LC-MS) untargeted lipidomic workflows\nfor additional isomer separation and high-confidence annotation, and\nthe emergence of high-resolution ion mobility (HRIM) strategies provides\nmarked improvements to the resolving power (<i>R</i><sub>p</sub> > 200) that can differentiate small structural differences\ncharacteristic of isomers. One such HRIM strategy, high-resolution\ndemultiplexing (HRdm), utilizes multiplexed drift tube ion mobility\nspectrometry (DTIMS) with post-acquisition algorithmic deconvolution\nto access high IM resolutions while retaining the measurement precision\ninherent to the drift tube technique; however, HRdm has yet to be\nutilized in untargeted studies. In this manuscript, a proof-of-concept\nstudy using ATP10D dysfunctional murine models was investigated to\ndemonstrate the utility of HRdm-incorporated untargeted lipidomic\nanalysis pipelines. Total lipid features were found to increase by\n2.5-fold with HRdm compared to demultiplexed DTIMS as a consequence\nof more isomeric lipids being resolved. An example lipid, PC 36:5,\nwas found to be significantly higher in dysfunctional ATP10D mice\nwith two resolved peaks observed by HRdm that were absent in both\nthe functional ATP10D mice and the standard demultiplexed DTIMS acquisition\nmode. The benefits of utilizing HRdm for discerning isomeric lipids\nin untargeted workflows have the potential to enhance our analytical\nunderstanding of lipids related to disease complexity and biologically\nrelevant studies.