Lipid Isomer Separation Using Travelling Wave Cyclic Ion Mobility Mass Spectrometry

Importance of Topic

Galactosylceramide (GalCer) and Glucosylceramide (GlcCer) differ only by the hydroxyl group position at C-4, while ganglioside GD1a and GD1b vary in sialic acid composition and sequence. These subtle structural differences cause significant changes in physicochemical properties and biological functions. Reliable separation of these isomers is essential for understanding their roles in biomedical research and quality control.

Study Objectives and Overview

• Demonstrate multi-pass ion mobility separation capability of the SELECT SERIES™ Cyclic™ spectrometer.
• Compare resolution performance for GalCer/GlcCer and GD1a/GD1b across different pass numbers.

Methodology and Instrumentation

Lipid standards (GalCer d18:1/18:0, GlcCer d18:1/18:0, GD1a d18:1/18:0, GD1b d18:1/18:0) were prepared at 1 ng/µL and infused at 5 µL/min into an ESI source. Selected ions were transmitted via quadrupole into the cyclic mobility cell for 1 to 20 passes to tune resolution.

Used Instrumentation

• SELECT SERIES™ Cyclic™ Ion Mobility Mass Spectrometer (Waters Corporation)
• Electrospray Ionization (ESI) source

Main Results and Discussion

• Baseline separation of GalCer and GlcCer achieved after 20 passes (arrival times: 42.67 ms vs. 41.39 ms; IMS resolution 290 Ω/ΔΩ).
• GD1a and GD1b resolved with five passes, reaching IMS resolution of 145 Ω/ΔΩ.
• Multi-pass cyclic ion mobility effectively scales separation performance by exploiting conformational differences of lipid isomers.

Benefits and Practical Applications

• Advanced structural characterization for lipidomics and biomarker discovery.
• Enhanced quality control in pharmaceutical and food industries by resolving closely related species.
• Flexible resolution tuning via multi-pass capability for diverse analytical challenges.

Future Trends and Potential Applications

• Integration into high-throughput lipidomics workflows for comprehensive profiling.
• Combination with tandem MS (MS/MS) for detailed structural elucidation.
• Application to other isomeric biomolecules (peptides, metabolites) using cyclic ion mobility.

Conclusion

The SELECT SERIES™ Cyclic™ ion mobility system provides exceptional resolution of structurally similar lipid isomers, enabling deeper insights into their biological functions. Its scalable resolution makes it a powerful tool for advanced lipid analysis across research and industrial settings.

Reference

• Isaac, G.; Olivos, H.; Plumb, R. S. Lipid Isomer Separation Using Travelling Wave Cyclic Ion Mobility Mass Spectrometry. Waters Corporation, Poster, 2022.