Separation of Ganglioside Isomers Using the SELECT SERIES™ Cyclic™ IMS

Importance of the Topic

Detailed understanding of ganglioside isomers is vital for elucidating lipid function in health and disease and for developing targeted biomarkers. The close structural similarity of GD1a and GD1b requires advanced analytical approaches to differentiate their unique physicochemical and biological properties.

Objectives and Study Overview

This study aimed to demonstrate the capability of the SELECT SERIES Cyclic IMS system, with its multi-pass ion mobility separation, to achieve complete baseline separation of GD1a (d18:1/18:0) and GD1b (d18:1/18:0) isomers at m/z 917.488 [M-2H]2−.

Methodology and Instrumentation

The approach involved direct infusion of porcine brain ganglioside standards in chloroform/methanol at 1 ng/mL into an electrospray ionization source operating in negative mode. Selected ions were transmitted through the cyclic IMS cell with up to five passes to increase mobility resolution.

Instrumentation Used

• SELECT SERIES Cyclic IMS system with multi-pass ion mobility cell
• Time-of-Flight mass analyzer
• MassLynx 4.2 software for data acquisition

Main Results and Discussion

With a single IMS pass (resolution ~65 Ω/ΔΩ), GD1a and GD1b remained coalesced. Two to four passes improved peak definition, with partial resolution (80% valley) at three passes (~110 Ω/ΔΩ) and near-baseline separation at four passes (~130 Ω/ΔΩ). Full baseline separation (ATDs at 41.22 and 42.58 ms) and resolution of 145 Ω/ΔΩ were achieved after five passes. Individual standards confirmed GD1b eluted earlier than GD1a.

Benefits and Practical Applications

• Scalable ion mobility resolution tailored to analytical challenges
• Rapid millisecond separations without extensive chromatography
• Enhanced confidence in isomer identification for lipidomics and biomarker discovery

Future Trends and Potential Applications

Emerging directions include coupling cyclic IMS with chromatographic separations for comprehensive lipid profiling, high-throughput screening of complex biological samples, and expanding isomer separation to other challenging lipid classes. These advancements can accelerate diagnostic method development and deepen insight into disease-associated lipid alterations.

Conclusion

The selective multi-pass capability of the SELECT SERIES Cyclic IMS provides a powerful and flexible solution for resolving isomeric gangliosides. Achieving an IMS resolution of 145 Ω/ΔΩ enabled clear differentiation of GD1a and GD1b, highlighting the system's value in advanced lipidomic investigations.

Reference

• Li Z, Zhang Q. Ganglioside Isomer Analysis Using Ion Polarity Switching Liquid Chromatography-Tandem Mass Spectrometry. Anal Bioanal Chem. 2021;413:3269–3279.
• Giles K, Ujma J, Wildgoose J, Pringle S, Richardson K, Langridge D, Green M. A Cyclic Ion Mobility-Mass Spectrometry System. Anal Chem. 2019;91:8564–8573.
• Ujma J, Ropartz D, Giles K, Richardson K, Langridge D, Wildgoose J, Green G, Pringle S. Cyclic Ion Mobility Mass Spectrometry Distinguishes Anomers and Open-Ring Forms of Pentasaccharides. J Am Soc Mass Spectrom. 2019;30:1028–1037.