Differential Ion Mobility Separations/Mass Spectrometry with High Resolution in Both Dimensions

Abstract

Strong orthogonality to mass spectrometry makes differential ion mobility spectrometry (FAIMS) a powerful tool for isomer separations. However, high FAIMS resolution has been achieved overall only with buffers rich in He or H 2 . That obstructed coupling to Fourier transform mass spectrometers operating under ultrahigh vacuum, but exceptional m/z resolution and accuracy of FTMS are indispensable for frontline biological and environmental applications. By raising the waveform amplitude to 6 kV, we enabled high FAIMS resolution using solely N 2 and thus straightforward integration with any MS platform: here Orbitrap XL with the electron transfer dissociation (ETD) option. The initial evaluation for complete histone tails (50 residues) with diverse post-translational modifications on alternative sites demonstrates a broad capability to separate and confidently identify the PTM localization variants in the middle−down range.

Proteoform Differentiation using Tandem Trapped Ion Mobility, Electron Capture Dissociation, and ToF Mass Spectrometry

“…[37][38][39] In particular, linear IMS (e.g., trapped IMS, TIMS) 40,41 and non-linear IMS (e.g., field asymmetric waveform IMS, FAIMS) 42 exhibited great potential in separating histone tail proteoforms. 43,44 While FAIMS has been coupled to ExD for investigating histone tail PTMs, 44,45 TIMS in tandem with ECD has only been demonstrated for the case of effective mobility separation and identification of isomeric glycans in an FT-ICR MS platform. 46 The recent introduction of the electromagnetostatic (EMS) 47,48 cell capable of performing ECD without the need for long reaction times or ultrahigh vacuum has opened new avenues for top-down analysis using MS/MS (e.g., triple quadrupole, [49][50][51] q-TOF [52][53][54] MS and Orbitrap [55][56][57][58] ), and more recently IMS-ToF-MS/MS platforms.…”

Identification and quantification of amino acids and related compounds based on Differential Mobility Spectrometry

“…Using methanol as an added modifier to N 2 as carrier gas, we already showed baseline separation of isomeric ions could be obtained in the case of sarcosine, α-and β-alanine, 44 as well as for the α-, β-, and -aminobutyric acid isomers. 45 As reported in the literature, adding of a fraction of He to the carrier gas 20,22,29 or increasing the waveform amplitude 21 should also be considered for high resolution DMS. Quantification of AAs and related compounds were achieved using our 3D quadrupole ion trap despite the intrinsic limitations of these instruments in terms of sensitivity and linear dynamic range.…”

“…17 Efforts toward separation of isobaric and isomeric species led to the development of high resolution instruments and/or methodologies. Within a decade, important progresses have been made with new types of instruments time- 18,19 and spacemobility 20,21 separation. Significant enhancement of the resolving power can also be achieved by introducing a fraction of He 22 or polar molecules 23 in the carrier gas, as found in particular for AAs.…”

Progress in methodologies and quality‐control strategies in protein cross‐linking mass spectrometry

“…In addition to the typical enrichment methods prior to mass spectrometry, ion mobility spectrometry can be utilized to fractionate peptides in the gas phase, offering another dimension of separation [115, 116]. Ions can be separated based on their physiochemical properties such as mass, shape, dipole moment, and charge, which has been shown to lower the percentage of linear peptides [117–119]. Recently, the application of a new generation ion mobility device, high‐field asymmetric waveform ion mobility spectrometry (FAIMS), has been reported to have a similar performance on cross‐link identification with SEC [120].…”