Mass Spectra and Yields of Intact Charged Biomolecules Ejected by Massive Cluster Impact for Bioimaging in a Time-of-Flight Secondary Ion Microscope

Anal Chem. 2015 Nov 3;87(21):10779-84. doi: 10.1021/acs.analchem.5b01802. Epub 2015 Oct 20.

Abstract

Impacts of massive, highly charged glycerol clusters (≳10(6) Da, ≳ ± 100 charges) have been used to eject intact charged molecules of peptides, lipids, and small proteins from pure solid samples, enabling imaging using these ion species in a time-of-flight secondary ion microscope with few-micrometer spatial resolution. Here, we report mass spectra and useful ion yields (ratio of intact charged molecules detected to molecules sputtered) for several molecular species-two peptides, bradykinin and angiotensin II; two lipids, phosphatidylcholine and sphingomyelin; Irganox 1010 (a detergent); insulin; and rhodamine B-and show that useful ion yields are high enough to enable bioimaging of peptides and lipids in biological samples with few-micrometer resolution and acceptable signals. For example, several hundred molecular ion counts should be detectable from a 3 × 3 μm(2) area of a pure lipid bilayer given appropriate instrumentation or tens of counts from a minor constituent of such a layer.

MeSH terms

  • Glycerol / chemistry*
  • Ions / chemistry
  • Lipids / chemistry*
  • Microscopy*
  • Microscopy, Energy-Filtering Transmission Electron / instrumentation*
  • Peptides / chemistry*
  • Spectrometry, Mass, Secondary Ion*

Substances

  • Ions
  • Lipids
  • Peptides
  • Glycerol