In situ isobaric lipid mapping by MALDI-ion mobility separation-mass spectrometry imaging

J Mass Spectrom. 2020 Sep;55(9):e4531. doi: 10.1002/jms.4531.

Abstract

The highly diverse chemical structures of lipids make their analysis directly from biological tissue sections extremely challenging. Here, we report the in situ mapping and identification of lipids in a freshwater crustacean Gammarus fossarum using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) in combination with an additional separation dimension using ion mobility spectrometry (IMS). The high-resolution trapped ion mobility spectrometry (TIMS) allowed efficient separation of isobaric/isomeric lipids showing distinct spatial distributions. The structures of the lipids were further characterized by MS/MS analysis. It is demonstrated that MALDI MSI with mobility separation is a powerful tool for distinguishing and localizing isobaric/isomeric lipids.

Keywords: MALDI; TIMS; ion mobility separation; lipid isomers; mass spectrometry imaging.

MeSH terms

  • Amphipoda / chemistry*
  • Animals
  • Female
  • Ion Mobility Spectrometry / methods*
  • Isomerism
  • Lipids / analysis*
  • Lipids / chemistry
  • Molecular Structure
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*
  • Tandem Mass Spectrometry

Substances

  • Lipids