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Updated: Jun 30, 2025
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Using a Cyclic Ion Mobility Spectrometer for Tandem Ion Mobility Experiments
Published on: January 20, 2022
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Toward Part-per-Million Precision in the Determination of an Ion's Collision Cross Section Using Multipass Cyclic Ion
Olivia Critch-Doran1, Kevin Jenkins1, Mahin Hashemihedeshi1
1Department of Chemistry, Memorial University of Newfoundland, 45 Arctic Ave., St. John's, Newfoundland and Labrador A1C 5S7, Canada.
Journal of the American Society for Mass Spectrometry
|March 18, 2024
Summary
Cyclic ion mobility (cIMS) enhances ion mobility and collision cross section (CCS) precision by increasing ion passes. This method achieves part-per-million (ppm) precision, improving the characterization of complex mixtures.
Area of Science:
- Analytical Chemistry
- Physical Chemistry
Background:
- Cyclic ion mobility (cIMS) allows ions multiple passes in a drift cell, increasing separation.
- The impact of multiple passes on measurement precision for ion mobility and collision cross section (CCS) is under investigation.
Purpose of the Study:
- To test if multiple passes in cIMS improve the precision of ion mobility and derived TWCCS measurements.
- To establish a method for achieving part-per-million (ppm) precision in TWCCS measurements.
Main Methods:
- Experiments were conducted using diverse compounds, including polycyclic aromatic hydrocarbons and drug molecules.
- Gas chromatographic atmospheric pressure chemical ionization and direct infusion electrospray ionization were employed.
- The effect of increasing the number of passes in the cIMS cell on drift time and TWCCS precision was analyzed.
Main Results:
- Average periodic drift time precision approached part-per-million (ppm) levels with approximately 100 passes.
- TWCCS precision was predicted to reach 100 ppm after 100 passes and <10 ppm after 150 passes.
- Experiments with over 100 passes yielded TWCCS values with within-run precisions between 15 and 117 ppm.
Conclusions:
- Increasing the number of passes in cIMS significantly improves the precision of ion mobility and TWCCS measurements.
- This enhanced precision may result from the mitigation of space-charge effects.
- A practical method for ppm-precision TWCCS measurements was demonstrated for analyzing unknown drug mixtures.
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