High-Resolution Differential Ion Mobility Separations Using Planar Analyzers at Elevated Dispersion Fields
Analyses of complex or isomeric mixtures increasingly involve ion mobility spectrometry/ mass spectrometry (IMS/MS). The IMS methods are grouped into conventional, based on the absolute ion mobility, and differential or field asymmetric waveform IMS (FAIMS), based on the mobility difference in strong and weak electric fields. The key attraction of FAIMS is substantial orthogonality to MS, and several FAIMS/MS platforms have been commercialized. However, the utility of FAIMS had been constrained by limited resolving power, typically R ~ 10 - 20. Recently, the use of helium/nitrogen mixtures comprising up to 75% He has enabled R > 100, with broad resolution gains allowing separation of previously “co-eluting” isomers. These performance metrics open major new FAIMS applications in proteomic and other biological analyses. Here, we show that raising the separation field by ~35% over the previous 21 kV/cm provides similar or better resolution at 50% He, while avoiding problems due to elevated gas pressure in the MS manifold upon excessive He intake. In particular, a resolving power of >200 has been achieved for multiply-charged peptides. The field heating of ions under these conditions appears to exceed that at higher He content but weaker separation field, inducing greater izomerization of fragile species.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 990540
- Report Number(s):
- PNNL-SA-72822; 20496; 24698; 400412000; TRN: US201020%%400
- Journal Information:
- Analytical Chemistry, 82(18):7649-7655, Vol. 82, Issue 18
- Country of Publication:
- United States
- Language:
- English
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