Resolving the Complexity of Spatial Lipidomics Using MALDI TIMS Imaging Mass Spectrometry

Anal Chem. 2020 Oct 6;92(19):13290-13297. doi: 10.1021/acs.analchem.0c02520. Epub 2020 Sep 9.

Abstract

Lipids are a structurally diverse class of molecules with important biological functions including cellular signaling and energy storage. Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) allows for direct mapping of biomolecules in tissues. Fully characterizing the structural diversity of lipids remains a challenge due to the presence of isobaric and isomeric species, which greatly complicates data interpretation when only m/z information is available. Integrating ion mobility separations aids in deconvoluting these complex mixtures and addressing the challenges of lipid IMS. Here, we demonstrate that a MALDI quadrupole time-of-flight (Q-TOF) mass spectrometer with trapped ion mobility spectrometry (TIMS) enables a >250% increase in the peak capacity during IMS experiments. MALDI TIMS-MS separation of lipid isomer standards, including sn backbone isomers, acyl chain isomers, and double-bond position and stereoisomers, is demonstrated. As a proof of concept, in situ separation and imaging of lipid isomers with distinct spatial distributions were performed using tissue sections from a whole-body mouse pup.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Ion Mobility Spectrometry
  • Lipidomics*
  • Lipids / analysis*
  • Mice
  • Mice, Inbred C57BL
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Substances

  • Lipids