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Updated: May 14, 2026

Optimal Preparation of Formalin Fixed Samples for Peptide Based Matrix Assisted Laser Desorption/Ionization Mass Spectrometry Imaging Workflows
Published on: January 16, 2018
Matrix-assisted laser desorption/ionization imaging protocol for in situ characterization of tryptic peptide identity
Ove J R Gustafsson1, James S Eddes, Stephan Meding
1Adelaide Proteomics Centre, School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, Australia, 5005.
Rationale:
Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry provides the means to map the in situ distribution of tryptic peptides in formalin-fixed clinical tissue samples. The ability to analyze clinical samples is of great importance to further developments in the imaging field. However, there is a requirement in this field of research for additional methods describing the characterization of tryptic peptides by MALDI imaging.
Methods And Results:
This protocol gives highly detailed instructions, with examples, for (1) successfully performing tryptic peptide MALDI imaging on formalin-fixed cancer tissue using a MALDI-TOF/TOF MS instrument, (2) tentatively generating identifications through nLC/MS/MS, and (3) validating these identifications by in situ MS/MS of peptides of interest.
Conclusions:
This protocol provides a detailed and straightforward description of the methods required for groups new to MALDI imaging to begin analysis of formalin-fixed clinical samples.
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