Influence of ionization volume and sample gas flow rate on separation power in gas chromatography-ion mobility spectrometry

authored by: Tim Kobelt, Martin Lippmann, Jannik Wuttke, Hanno Wessel, Stefan Zimmermann
Abstract: In this work, the influence of the sample gas flow rate and the ionization region volume of an ion mobility spectrometer (IMS) used as a detector in gas chromatography (GC) on GC-IMS peak shape has been investigated. Therefore, a drift tube IMS with a field-switching ion shutter, a defined ionization region volume and an ultra-violet radiation source was used. To identify the influence of the sample gas flow rate entering the ionization region (equals the GC carrier gas flow rate if no further make-up gas is used) and the ionization region volume on peak broadening and signal intensity, different sample volumes as they would elute from a GC were tested at a variety of sample gas flow rates at a given ionization region volume. The results clearly show that for low sample gas flow rates a depletion of sample molecules in the ionization region leads to a significant decrease in effective detector volume but also to reduced signal intensities. Therefore, for optimal performance of a GC-IMS, the optimal operating point of the GC should match the flow range, where the IMS provides the best compromise between signal-to-noise ratio and peak broadening.
Organisation(s): Sensors and Measurement Technology Section
Type: Article
Journal: Journal of Chromatography A
Volume: 1713
No. of pages: 8
ISSN: 0021-9673
Publication date: 04.01.2024
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Analytical Chemistry, Biochemistry, Organic Chemistry
Electronic version(s): https://doi.org/10.1016/j.chroma.2023.464506 (Access: Closed)

BibTeX

@article{672aa7e61b984b7a8ce4cde2ccb70f22,
title = "Influence of ionization volume and sample gas flow rate on separation power in gas chromatography-ion mobility spectrometry",
abstract = "In this work, the influence of the sample gas flow rate and the ionization region volume of an ion mobility spectrometer (IMS) used as a detector in gas chromatography (GC) on GC-IMS peak shape has been investigated. Therefore, a drift tube IMS with a field-switching ion shutter, a defined ionization region volume and an ultra-violet radiation source was used. To identify the influence of the sample gas flow rate entering the ionization region (equals the GC carrier gas flow rate if no further make-up gas is used) and the ionization region volume on peak broadening and signal intensity, different sample volumes as they would elute from a GC were tested at a variety of sample gas flow rates at a given ionization region volume. The results clearly show that for low sample gas flow rates a depletion of sample molecules in the ionization region leads to a significant decrease in effective detector volume but also to reduced signal intensities. Therefore, for optimal performance of a GC-IMS, the optimal operating point of the GC should match the flow range, where the IMS provides the best compromise between signal-to-noise ratio and peak broadening.",
keywords = "Effective detector volume, GC-IMS, Ionization volume, Peak broadening",
author = "Tim Kobelt and Martin Lippmann and Jannik Wuttke and Hanno Wessel and Stefan Zimmermann",
note = "Funding Information: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – SFB/TRR-298-SIIRI – Project-ID 426335750. ",
year = "2024",
month = jan,
day = "4",
doi = "10.1016/j.chroma.2023.464506",
language = "English",
volume = "1713",
journal = "Journal of Chromatography A",
issn = "0021-9673",
publisher = "Elsevier",
}