Measurement of Individual Ions Sharply Increases the Resolution of Orbitrap Mass Spectra of Proteins

Jared O. Kafader, Rafael D. Melani, Michael W. Senko, Alexander A. Makarov, Neil L. Kelleher, Philip D. Compton*

*Corresponding author for this work

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

It is well-known that with Orbitrap-based Fourier-transform-mass-spectrometry (FT-MS) analysis, longer-time-domain signals are needed to better resolve species of interest. Unfortunately, increasing the signal-acquisition period comes at the expense of increasing ion decay, which lowers signal-to-noise ratios and ultimately limits resolution. This is especially problematic for intact proteins, including antibodies, which demonstrate rapid decay because of their larger collisional cross-sections, and result in more frequent collisions with background gas molecules. Provided here is a method that utilizes numerous low-ion-count spectra and single-ion processing to reconstruct a conventional m/z spectrum. This technique has been applied to proteins varying in molecular weight from 8 to 150 kDa, with a resolving power of 677»000 achieved for transients of carbonic anhydrase (29 kDa) with a duration of only 250 ms. A resolution improvement ranging from 10-to 20-fold was observed for all proteins, providing isotopic resolution where none was previously present.

Original languageEnglish (US)
Pages (from-to)2776-2783
Number of pages8
JournalAnalytical Chemistry
Volume91
Issue number4
DOIs
StatePublished - Feb 19 2019

ASJC Scopus subject areas

  • Analytical Chemistry

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