Gauthier Eppe on Ion Mobility–HRMS for Complex Environmental Pollutants

At analytica 2026 in Munich, Germany, LCGC International spoke with Gauthier Eppe from the University of Liege about his presentation, “Good Resolutions for Bad Pollutants: Ion Mobility–HRMS to Resolve Complex Environmental Mixtures.”¹ Environmental samples often contain thousands of anthropogenic and naturally occurring compounds, posing substantial challenges for analytical resolution and confident identification. Among these, halogenated persistent organic pollutants (POPs) remain of particular concern due to their longevity, toxicity, and bioaccumulation potential.

In this video interview, Eppe answers the following question:

• GC–HRMS is considered the gold standard for semi-volatile contaminants. What were the specific analytical limitations you kept encountering in practice that drove you to add ion mobility as an extra dimension?

Eppe’s research explores how coupling high-resolution ion mobility with high-resolution time-of-flight mass spectrometry (TOF-MS) can overcome traditional limitations in gas chromatography–high-resolution mass spectrometry (GC–HRMS) workflows, especially when analyzing non-targeted and suspect compounds in complex matrices. The developed GC-APCI-tims-TOF-MS platform introduces an orthogonal separation dimension that delivers structural insight through collision cross-section (CCS) values, enhancing selectivity and identification confidence.

Central to this work is the establishment of a robust CCS calibration strategy that leverages poly-siloxane background ions as real-time internal calibrants, ensuring stable, reproducible measurements. Eppe’s team also introduced Sliding Windows in Ion Mobility (SWIM), a novel acquisition approach that exploits predictable retention time–CCS correlations within halogenated POP families.² SWIM improves mobility resolving power by approximately 40% without compromising accuracy or signal fidelity.

Applied across multiple POP subclasses, the approach improved pollutant identification, quantitative measurement, and the assessment of emerging contaminants in complex mixtures.

Eppe is full professor at the University of Liège, director of the MSLab, and director of the research unit Molecular Systems (MolSys).

References

1. Eppe, G. Good Resolutions for Bad Pollutants: Ion Mobility–HRMS to Resolve Complex Environmental Mixtures. Presented at analytica 2026, in Munich, Germany. https://analytica.de/en/event-program/conference/lecture/good-resolutions-for-bad-pollutants-ion-mobilityhrms-to-resolve-complex-environmental-mixtures-16240/ (accessed 2026-04-08).
2. Muller, B. H.; Scholl, G.; Far, J.; De Pauw, E.; Eppe G. Sliding Windows in Ion Mobility (SWIM): a New Approach to Increase the Resolving Power in Trapped Ion Mobility-Mass Spectrometry Hyphenated with Chromatography. Anal Chem 2023, 95 (48), 17586–17594.