Agilent 6560 Ion Mobility LC/Q-TOF

Importance of Topic

Ion mobility mass spectrometry (IM-MS) adds a powerful third dimension to liquid chromatography–mass spectrometry (LC-MS) workflows by separating ions based on their size, shape, and charge. This orthogonal separation improves the characterization of small molecules, peptides, proteins, metabolites, lipids, and biotherapeutics, unlocking deeper insights into complex biological and environmental samples.

Objectives and Overview of the Study

This white paper introduces the Agilent 6560 Ion Mobility LC/Q-TOF system and demonstrates its capabilities: ultrahigh sensitivity, accurate collision cross section (CCS) measurement, collision-induced unfolding (CIU), and multiplexing. The goal is to show how this platform enhances analyte resolution, structural characterization, and workflow efficiency for proteomics, metabolomics, glycomics, lipidomics, and biotherapeutic development.

Methodology

The approach couples reverse-phase or hydrophilic interaction liquid chromatography with a uniform-field drift tube ion mobility cell and a high-resolution quadrupole-time-of-flight mass analyzer. Key techniques include:

• Low-energy drift tube design to preserve native conformations.
• Multiplexing with post-processing high-resolution demultiplexing.
• Collision-induced unfolding experiments to probe protein stability.
• All Ions fragmentation for untargeted compound screening.
• First-principles CCS calculation without external calibration.

Instrumental Setup

This system integrates:

• Agilent 1200 Infinity Series or UHPLC front end.
• Dual electrodynamic iFunnel assembly for ion focusing and enrichment.
• Uniform-field drift tube for CCS measurements (≤2% error, repeatability <0.3% RSD).
• JetStream electrospray interface and capillary with VacShield for robust performance.
• High-resolution Q-TOF analyzer for accurate mass (<2 ppm) and All Ions MS/MS.
• Agilent MassHunter IM-MS Browser and Mass Profiler software for visualization, filtering, and CCS calculation.

Main Results and Discussion

Studies highlighted include:

• Separation of isomeric tryptic peptides in mouse plasma, revealing ten unique peptides in LC-IM-Q-TOF data.
• Detection of low-level peptides (“needle in a haystack”) at high pg/mL concentrations by exploiting ion mobility selectivity and multiplexing.
• Pan-omic mapping of lipids, peptides, and carbohydrates in direct infusion experiments, with conformational class separation by CCS and m/z.
• CIU fingerprinting of IgG subclasses, distinguishing disulfide bonding arrangements and conformations with root-mean-square deviations <5% for replicates.
• Rapid glycan isomer differentiation using high-resolution conformer distribution fingerprinting and CCS values without MSn.
• Annotation of unknown metabolites (e.g., adenosine) in untargeted workflows by matching accurate mass and CCS to literature values within 0.2%.

Benefits and Practical Applications

The 6560 platform delivers:

• Enhanced peak capacity through combined LC, IM, and MS separations.
• Reliable CCS reference standards via Agilent Tune Mix interlaboratory study.
• Fast, label-free CIU screening for biotherapeutic stability and biosimilar comparison.
• All Ions fragmentation with drift-time filtering to detect trace analytes in complex matrices.
• Pan-omics profiling for systems biology, enabling untargeted surveys of proteome, metabolome, lipidome, and glycome.

Future Trends and Potential Applications

Emerging directions include:

• Integration with high-throughput screening and automation for drug discovery pipelines.
• Advanced data analytics and machine learning on multidimensional IM-MS datasets.
• Expanded CCS libraries covering novel metabolites, lipids, and modified proteins.
• Real-time process monitoring in biomanufacturing and quality control using CIU.
• Structural biology studies of large protein complexes and membrane assemblies via native MS and IM.

Conclusion

The Agilent 6560 Ion Mobility LC/Q-TOF instrument extends conventional LC-MS by adding robust, high-resolution ion mobility separation. Its first-principles CCS accuracy, CIU capabilities, and multiplexed workflows transform structural characterization across small molecules, biomolecules, and complex mixtures. This platform empowers laboratories to reveal previously hidden chemical details, accelerate discovery, and improve analytical confidence.

References

1. May, J.C., et al. Conformational Ordering of Biomolecules in the Gas-Phase: Nitrogen Collision Cross-Sections Measured on a Prototype High Resolution Drift Tube Ion Mobility-Mass Spectrometer. Anal Chem. 2014;86(4):2107–2116.
2. Damerell, D., et al. The GlycanBuilder and GlycoWorkbench Glycoinformatics Tools: Updates and New Developments. Biol Chem. 2012;393(11):1357–1362.
3. Sastre Torano, J., et al. Ion-Mobility Spectrometry Can Assign Exact Fucosyl Positions in Glycans and Prevent Misinterpretation of MS Data after Gas-Phase Rearrangement. Angew Chem Int Ed. 2019;58(49):17616–17620.
4. Sastre Torano, J., et al. Identification of Isomeric N-Glycans by Conformer Distribution Fingerprinting Using Ion Mobility Mass Spectrometry. Chem Eur J. 2021;27(6):2149–2154.