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Updated: Jun 14, 2026

Atmospheric-pressure Molecular Imaging of Biological Tissues and Biofilms by LAESI Mass Spectrometry
Published on: September 3, 2010
Electrospray-assisted laser desorption ionization mass spectrometry (ELDI-MS) with an infrared laser for
Ivory X Peng1, Rachel R Ogorzalek Loo, Eli Margalith
1Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095, USA.
Abstract:
An electrospray-assisted laser desorption/ionization source with an infrared OPO laser (IR-ELDI) was constructed and optimized for peptide and protein mass spectrometry analysis. Similar to ELDI with an ultraviolet laser, IR-ELDI generates multiply charged molecules for peptides and proteins measured under ambient sampling conditions. Both samples in the dried state and analyte solutions can be directly measured by IR-ELDI without the presence of a conventional MALDI matrix. However, the analysis of sample solutions is shown to greatly enhance the sensitivity of the mass spectrometry measurement, as a 100-fold sensitivity gain for peptide measurements was measured. The limit of detection of IR-ELDI was determined to be 250 fmol for bradykinin (1.1 kDa), 100 fmol for ubiquitin (8.6 kDa), and 500 fmol for carbonic anhydrase (29 kDa). IR-ELDI is amenable for MS and MSn analysis for proteins up to 80 kDa transferrin. IR-ELDI-MS may be a useful tool for protein sequencing analysis from complex biological matrices, with minimal sample preparation required.
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