An investigation on the mechanism of sublimed DHB matrix on molecular ion yields in SIMS imaging of brain tissue
Artikel i vetenskaplig tidskrift, 2016

We have characterized the use of sublimation to deposit matrix-assisted laser desorption/ionization (MALDI) matrices in secondary ion mass spectrometry (SIMS) analysis, i.e. matrix-enhanced SIMS (ME-SIMS), a common surface modification method to enhance sensitivity for larger molecules and to increase the production of intact molecular ions. We use sublimation to apply a thin layer of a conventional MALDI matrix, 2,5-dihydroxybenzoic acid (DHB), onto rat brain cerebellum tissue to show how this technique can be used to enhance molecular yields in SIMS while still retaining a lateral resolution around 2 mu m and also to investigate the mechanism of this enhancement. The results here illustrate that cholesterol, which is a dominant lipid species in the brain, is decreased on the tissue surface after deposition of matrix, particularly in white matter. The decrease of cholesterol is followed by an increased ion yield of several other lipid species. Depth profiling of the sublimed rat brain reveals that the lipid species are de facto extracted by the DHB matrix and concentrated in the top most layers of the sublimed matrix. This extraction/concentration of lipids directly leads to an increase of higher mass lipid ion yield. It is also possible that the decrease of cholesterol decreases the potential suppression of ion yield caused by cholesterol migration to the tissue surface. This result provides us with significant insights into the possible mechanisms involved when using sublimation to deposit this matrix in ME-SIMS.

sample preparation

Cholesterol migration

sensitivity

tof-sims

lipids

Biochemistry & Molecular Biology

enhancement

ME-SIMS mechanism

beams

MS imaging

surface

discovery

maldi-ms

Chemistry

desorption/ionization mass-spectrometry

Författare

Masoumeh Dowlatshahi Pour

Chalmers, Kemi och kemiteknik, Kemi och biokemi, Analytisk kemi

Per Malmberg

Chalmers, Kemi och kemiteknik, Kemi och biokemi, Analytisk kemi

Andrew Ewing

Chalmers, Kemi och kemiteknik, Kemi och biokemi, Analytisk kemi

Göteborgs universitet

Analytical and Bioanalytical Chemistry

1618-2642 (ISSN) 1618-2650 (eISSN)

Vol. 408 12 3071-3081

Ämneskategorier

Biokemi och molekylärbiologi

Kemi

DOI

10.1007/s00216-016-9385-3

PubMed

26922337

Mer information

Skapat

2017-10-07