Details
| Original language | English |
|---|---|
| Pages (from-to) | 9960-9969 |
| Number of pages | 10 |
| Journal | Analytical chemistry |
| Volume | 94 |
| Issue number | 28 |
| Early online date | 6 Jul 2022 |
| Publication status | Published - 19 Jul 2022 |
Abstract
Efficient ionization of analyte molecules is a crucial step for the outstanding sensitivity of ion mobility spectrometers (IMS) used for trace gas detection. Here, we present a new ion source that combines the previously published extended field switching ion shutter with two switchable ionization sources and an optimized sample gas flow that leads to a focused laminar stream through the reaction region of the ion source. The X-ray ionization source allows for chemical gas phase ionization of analyte molecules, while the UV ionization source allows for direct ionization of analyte molecules. The optimized sample gas flow not only allows for quickly washing out analyte molecules from the reaction region but also has improved sensitivity by a factor of about 5 for protonated monomers, 20 for proton-bound dimers, and over 100 for the proton-bound trimer of 1-octanol. The resulting limits of detection using chemical X-ray ionization are in the subppt v-range for protonated monomers and in the low ppt v-range for proton-bound dimers, while the limits of detection using direct UV ionization are in the subppb v-range. Especially, a direct comparison between chemical and direct ionization of ketones using this ultrasensitive ion source reveals a stepwise conversion from directly ionized monomers to proton-bound dimers via protonated monomers during direct UV ionization.
ASJC Scopus subject areas
- Chemistry(all)
- Analytical Chemistry
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In: Analytical chemistry, Vol. 94, No. 28, 19.07.2022, p. 9960-9969.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Ultrasensitive Ion Source for Drift Tube Ion Mobility Spectrometers Combining Optimized Sample Gas Flow with Both Chemical Ionization and Direct Ionization
AU - Kirk, Ansgar T.
AU - Kueddelsmann, Maximilian J.
AU - Zimmermann, Stefan
N1 - Funding Information: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 263334553.
PY - 2022/7/19
Y1 - 2022/7/19
N2 - Efficient ionization of analyte molecules is a crucial step for the outstanding sensitivity of ion mobility spectrometers (IMS) used for trace gas detection. Here, we present a new ion source that combines the previously published extended field switching ion shutter with two switchable ionization sources and an optimized sample gas flow that leads to a focused laminar stream through the reaction region of the ion source. The X-ray ionization source allows for chemical gas phase ionization of analyte molecules, while the UV ionization source allows for direct ionization of analyte molecules. The optimized sample gas flow not only allows for quickly washing out analyte molecules from the reaction region but also has improved sensitivity by a factor of about 5 for protonated monomers, 20 for proton-bound dimers, and over 100 for the proton-bound trimer of 1-octanol. The resulting limits of detection using chemical X-ray ionization are in the subppt v-range for protonated monomers and in the low ppt v-range for proton-bound dimers, while the limits of detection using direct UV ionization are in the subppb v-range. Especially, a direct comparison between chemical and direct ionization of ketones using this ultrasensitive ion source reveals a stepwise conversion from directly ionized monomers to proton-bound dimers via protonated monomers during direct UV ionization.
AB - Efficient ionization of analyte molecules is a crucial step for the outstanding sensitivity of ion mobility spectrometers (IMS) used for trace gas detection. Here, we present a new ion source that combines the previously published extended field switching ion shutter with two switchable ionization sources and an optimized sample gas flow that leads to a focused laminar stream through the reaction region of the ion source. The X-ray ionization source allows for chemical gas phase ionization of analyte molecules, while the UV ionization source allows for direct ionization of analyte molecules. The optimized sample gas flow not only allows for quickly washing out analyte molecules from the reaction region but also has improved sensitivity by a factor of about 5 for protonated monomers, 20 for proton-bound dimers, and over 100 for the proton-bound trimer of 1-octanol. The resulting limits of detection using chemical X-ray ionization are in the subppt v-range for protonated monomers and in the low ppt v-range for proton-bound dimers, while the limits of detection using direct UV ionization are in the subppb v-range. Especially, a direct comparison between chemical and direct ionization of ketones using this ultrasensitive ion source reveals a stepwise conversion from directly ionized monomers to proton-bound dimers via protonated monomers during direct UV ionization.
UR - http://www.scopus.com/inward/record.url?scp=85135936971&partnerID=8YFLogxK
U2 - 10.1021/acs.analchem.2c00955
DO - 10.1021/acs.analchem.2c00955
M3 - Article
VL - 94
SP - 9960
EP - 9969
JO - Analytical chemistry
JF - Analytical chemistry
SN - 0003-2700
IS - 28
ER -