Absorption mode for FT-MS

There has been much recent interest in the development of absorption mode Fourier transform mass spectrometry data (either from FT-ICR MS or Orbitrap systems) presentation, as an alternative to the normal magnitude mode. Viewing the same Fourier transform mass spectrometry data in absorption mode offers benefits in terms of improved mass resolving power, mass accuracy and signal-to-noise ratio.  And all this without having to make expensive upgrades to the instrument.

benefits of phasing annotated fullIn this figure you can see the benefits that “phasing” brings.  Notice how the resolution is improved.  In particular, note how the peaks at the upper mass end of this spectral portion are resolving in absorption mode but are unresolved in magnitude mode.

Mass resolving power is one of the key performance metrics of mass spectrometers. Increased mass resolving power, and associated benefits such as improved mass accuracy, is particularly beneficial for the study of both complex mixtures (for example natural organic matter or crude oil) and very large molecules (for example bio-macromolecules such as proteins or synthetic polymers).


The Kilgour Labs have developed Autophaser – a tool to allow FT-MS users to easily access the benefits of absorption mode in their work.  The Autophaser tool is commercially available through our partners SpectroSwiss.

New features for Autophaser are always being developed, however, and the Kilgour Lab is always looking for collaborators who are interested in testing and requesting new capabilities.  If you are interested – get in touch.  We will be more than happy to demonstrate the capability we currently have on spectra you provide.

We are currently working developing a new top-down proteomics sequencing tool as part of the Autophaser suite and that makes use of our new, improved peak detection algorithm.