A new review paper by Kristian E. Swearingen and Robert L. Moritz has just been published in the journal ‘Expert Review of Proteomics’.
It covers the use of cylindrical, planar and miniaturized ultra-high field FAIMS devices as additional separation steps after liquid chromatography and prior to mass spectrometry (i.e. LC-FAIMS-MS) for proteomics studies. Initially the authors discuss why additional gas-phase ion separation is a desirable way of achieving additional selectivity when dealing with complex samples. An outline of the basic FAIMS concept and the history of its development are given as well as a discussion on the coupling of Electrospray Ionization (ESI) to FAIMS devices. A section is devoted each to reviewing the pros and cons of cylindrical, planar and miniaturized ultra-high field FAIMS devices, including simplified instrument schematics.
Having reviewed the existing literature, Swearingen and Moritz find that FAIMS produces robust and repeatable results and that it is well suited as an additional separation stage. They state that FAIMS:
- Improves peptide discovery by decreasing sample complexity.
- Enables detection of co-eluting species with similar m/z by providing separation that is orthogonal to both LC and MS.
- Improves dynamic range and limits of detection by reducing chemical noise.
The review will be of great interest to proteomics researchers and to others who are interested in the separation and characterisation of complex mixtures. Take a look for yourselves!
High-Field Asymmetric Waveform Ion Mobility Spectrometry for Mass Spectrometry-Based Proteomics
Kristian E. Swearingen1 and Robert L. Moritz1
Expert Review of Proteomics
October 2012, Vol. 9, No. 5, Pages 505-517 , DOI 10.1586/epr.12.50
1. Institute for Systems Biology, Seattle, WA, USA
Abstract: High-field asymmetric waveform ion mobility spectrometry (FAIMS) is an atmospheric pressure ion mobility technique that separates gas-phase ions by their behavior in strong and weak electric fields. FAIMS is easily interfaced with electrospray ionization and has been implemented as an additional separation mode between liquid chromatography (LC) and mass spectrometry (MS) in proteomic studies. FAIMS separation is orthogonal to both LC and MS and is used as a means of on-line fractionation to improve the detection of peptides in complex samples. FAIMS improves dynamic range and concomitantly the detection limits of ions by filtering out chemical noise. FAIMS can also be used to remove interfering ion species and to select peptide charge states optimal for identification by tandem MS. Here, the authors review recent developments in LC-FAIMS-MS and its application to MS-based proteomics.