Ion Mobility
Ion Mobility - Related Videos
08:40
Using a Cyclic Ion Mobility Spectrometer for Tandem Ion Mobility Experiments
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Cited by 2 •
2022
Ion mobility spectrometry (IMS) is an interesting complement to mass spectrometry for the characterization of biomolecules, notably because it is sensitive to isomerism. This protocol describes a tandem IMS (IMS/IMS) experiment, which allows the isolation of a molecule and the generation of the mobility profiles of its fragments.
16:40
T-wave Ion Mobility-mass Spectrometry: Basic Experimental Procedures for Protein Complex Analysis
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Cited by 51 •
2010
Ion mobility-mass spectrometry is an emerging gas-phase technology that separates ions, based on their collision cross-section and mass. The method provides three-dimensional information on the overall topology and shape of protein complexes. Here, we outline a basic procedure for instrument setting and optimization, calibration of drift times, and data interpretation.
16:11
Thermochemical Studies of Ni(II) and Zn(II) Ternary Complexes Using Ion Mobility-Mass Spectrometry
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Cited by 5 •
2022
This article describes an experimental protocol using electrospray-ion mobility-mass spectrometry, semi-empirical quantum calculations, and energy-resolved threshold collision-induced dissociation to measure the relative thermochemistry of the dissociation of related ternary metal complexes.
11:09
An HS-MRM Assay for the Quantification of Host-cell Proteins in Protein Biopharmaceuticals by Liquid Chromatography Ion Mobility QTOF Mass Spectrometry
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Cited by 9 •
2018
Here, we describe a chromatographic assay coupled with the ion mobility separation of peptide precursors followed by the high-resolution (~30,000) MS-detection of peptide fragments for the quantification of spiked peptide standards in a monoclonal antibody digest.
08:52
Ion-Exchange Chromatography
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2023
Source: Laboratory of Dr. B. Jill Venton - University of Virginia Ion-exchange chromatography is a type of chromatography that separates analytes based on charge. A column is used that is filled with a charged stationary phase on a solid support, called an ion-exchange resin. Strong cation-exchange chromatography preferentially separates out cations by using a negatively-charged resin while strong anion-exchange chromatography preferentially selects out anions by using a positively-charged...
FAQs
Mobility reflects more than an ion’s mass-to-charge ratio. Charge affects its response to the electric field, while size and shape influence how it encounters the buffer gas; interactions with that gas further modify movement. Consequently, ions sharing related mass-to-charge values can still travel differently, providing an additional basis for chemical discrimination.
Mass spectrometry organizes ions primarily by mass-to-charge ratio, whereas ion mobility adds a movement-based measurement. If two species have similar mass-to-charge values but differ in dimensions, conformation, shape, or gas interactions, their mobilities can differ. This complementary separation helps distinguish chemically related species that would otherwise be difficult to resolve.
Collision cross section, or CCS, supplies information related to how an ion interacts with collisions in the surrounding gas. It complements mass-to-charge data by contributing structural information associated with molecular dimensions and shape. In chemical analysis, CCS measurements can help compare ions with similar composition but different conformations or arrangements.
Coupling creates an additional dimension of evidence: mass-to-charge information describes composition-related differences, while mobility reports differences in gas-phase movement. Interpreting both measurements can improve identification and characterization in complex mixtures, where several species may have comparable mass-to-charge ratios. The combined approach is especially useful when structural, conformational, or isomeric distinctions matter.
The technique is particularly useful for complex mixtures and for molecules whose structures cannot be distinguished adequately from mass-to-charge information alone. Supported applications include examining molecular conformations, separating or characterizing isomers, studying biomolecules, and analyzing reaction products. These uses make ion mobility relevant when researchers need compositional evidence together with additional structural information.
An experiment can add mobility-based evidence to a product’s mass-to-charge measurement, helping determine whether chemically related species differ in size, shape, charge, or interactions with the buffer gas. When coupled with mass spectrometry, these observations support product identification and characterization, especially in mixtures containing multiple species or structurally distinct products.