Lecture
Good Resolutions for Bad Pollutants: Ion Mobility–HRMS to Resolve Complex Environmental Mixtures
- at -
- ICM Saal 5
- Type: Lecture
Lecture description
Environmental mixtures contain thousands of anthropogenic and naturally occurring chemicals, with halogenated persistent organic pollutants (POPs) remaining among the most concerning due to their toxicity, persistence, and bioaccumulation. While GCHRMS are established gold standard method for semi-volatile contaminants, complex matrices and pervasive coelutions (isobars, isomers, in-source fragments) still limit selectivity and confidence in identification, especially in non-targeted and suspected screening workflows. Here, we show how coupling high-resolution ion mobility to high resolution TOFMS strengthens pollutant analysis by adding an orthogonal separation dimension and structure-informative metrics (e.g., collision cross sections, CCS), thereby improving selectivity and confidence in identification.
We developed and optimized a GC-APCI-tims-TOFMS platform (timsTOF pro2, Bruker, Bremen) dedicated to GC-amenable halogenated contaminants. A robust CCS calibration strategy was established despite the constraints of GC-APCI, leveraging ubiquitous background poly-siloxane ions as real-time internal calibrants, enabling rapid post-acquisition correction and improved long-term reproducibility. Instrumental parameters governing transmission, fragmentation, and resolving power were systematically tuned, and a Sliding Windows in Ion Mobility (SWIM) acquisition strategy was introduced (1). SWIM exploits predictable retention time-CCS relationships within halogenated POP families to narrow the scanned mobility range per chromatographic segment, yielding ~40% higher mobility resolving power without sacrificing CCS accuracy or signal intensity.
Across multiple POP subclasses, tims added selectivity for discriminating coeluting isobars and mitigating fragment interferences, while CCS provided an additional confirmation criterion alongside retention time and isotopic information (including close CCS agreement between native and 13C-labelled standards). Quantitative performance was evaluated for ultra-trace dioxins and PCBs in fat-rich matrices, demonstrating regulatory-compatible linearity, precision, and trueness with enhanced selectivity versus conventional workflows (2). Overall, GC-APCI-tims-TOFMS platform provides a powerful multidimensional strategy to resolve complex environmental mixtures and strengthen both targeted compliance analysis and exploratory screening.
Keywords: ion mobility, TIMS, HRMS, CCS, GC-APCI, persistent organic pollutants, non-target and suspected screening, complex matrices
(1) Muller B. H., Scholl G., Far J., De Pauw, E. and 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.
(2) Muller B. H., Scholl G. and Eppe G. Gas Chromatography-trapped ion mobility mass spectrometry: A highly specific and ultra-sensitive platform for quantitative subppt levels of dioxins and PCBs in food, Chemosphere, 2025, 144557
We developed and optimized a GC-APCI-tims-TOFMS platform (timsTOF pro2, Bruker, Bremen) dedicated to GC-amenable halogenated contaminants. A robust CCS calibration strategy was established despite the constraints of GC-APCI, leveraging ubiquitous background poly-siloxane ions as real-time internal calibrants, enabling rapid post-acquisition correction and improved long-term reproducibility. Instrumental parameters governing transmission, fragmentation, and resolving power were systematically tuned, and a Sliding Windows in Ion Mobility (SWIM) acquisition strategy was introduced (1). SWIM exploits predictable retention time-CCS relationships within halogenated POP families to narrow the scanned mobility range per chromatographic segment, yielding ~40% higher mobility resolving power without sacrificing CCS accuracy or signal intensity.
Across multiple POP subclasses, tims added selectivity for discriminating coeluting isobars and mitigating fragment interferences, while CCS provided an additional confirmation criterion alongside retention time and isotopic information (including close CCS agreement between native and 13C-labelled standards). Quantitative performance was evaluated for ultra-trace dioxins and PCBs in fat-rich matrices, demonstrating regulatory-compatible linearity, precision, and trueness with enhanced selectivity versus conventional workflows (2). Overall, GC-APCI-tims-TOFMS platform provides a powerful multidimensional strategy to resolve complex environmental mixtures and strengthen both targeted compliance analysis and exploratory screening.
Keywords: ion mobility, TIMS, HRMS, CCS, GC-APCI, persistent organic pollutants, non-target and suspected screening, complex matrices
(1) Muller B. H., Scholl G., Far J., De Pauw, E. and 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.
(2) Muller B. H., Scholl G. and Eppe G. Gas Chromatography-trapped ion mobility mass spectrometry: A highly specific and ultra-sensitive platform for quantitative subppt levels of dioxins and PCBs in food, Chemosphere, 2025, 144557
