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Hitzemann M, Schaefer C, Kirk AT, Nitschke A, Lippmann M, Zimmermann S. Easy to assemble dielectric barrier discharge plasma ionization source based on printed circuit boards. Anal Chim Acta 2023; 1239:340649. [PMID: 36628746 DOI: 10.1016/j.aca.2022.340649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 11/14/2022] [Accepted: 11/20/2022] [Indexed: 11/29/2022]
Abstract
Here, we present a new and an easy to assemble dielectric barrier discharge plasma ionization source based on printed circuit boards with two parallel isolated electrodes for generating a plasma inside an inert fused silica capillary. For demonstration, this plasma source is coupled to an ion mobility spectrometer. With two different sample gas feeds the analytes can either pass through the plasma or bypass the plasma before entering the reaction region of the ion mobility spectrometer, allowing for different ionization pathways, e.g. electron impact ionization, ionization by excited species, e.g. helium metastables, or chemical ionization via reactant ions generated inside or downstream of the plasma. The plasma source, in particular, the electrode geometry and the capillary diameter were designed with the help of electric field simulations. A rectangular electrode with a height of at least twice the outer diameter of the capillary turned out to be ideal, in both the simulation and the experiment. Furthermore, a simple control electronics has been developed, which can be easily applied to other plasma sources. With the plasma source presented here, detection limits in the mid pptv range have been reached.
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Affiliation(s)
- Moritz Hitzemann
- Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstr. 9A, 30167, Hannover, Germany.
| | - Christoph Schaefer
- Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstr. 9A, 30167, Hannover, Germany
| | - Ansgar T Kirk
- Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstr. 9A, 30167, Hannover, Germany
| | - Alexander Nitschke
- Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstr. 9A, 30167, Hannover, Germany
| | - Martin Lippmann
- Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstr. 9A, 30167, Hannover, Germany
| | - Stefan Zimmermann
- Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstr. 9A, 30167, Hannover, Germany
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Kirk AT, Kueddelsmann MJ, Zimmermann S. Ultrasensitive Ion Source for Drift Tube Ion Mobility Spectrometers Combining Optimized Sample Gas Flow with Both Chemical Ionization and Direct Ionization. Anal Chem 2022; 94:9960-9969. [PMID: 35793469 DOI: 10.1021/acs.analchem.2c00955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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 subpptv-range for protonated monomers and in the low pptv-range for proton-bound dimers, while the limits of detection using direct UV ionization are in the subppbv-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.
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Affiliation(s)
- Ansgar T Kirk
- Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Department of Sensors and Measurement Technology, 30167 Hannover, Germany
| | - Maximilian J Kueddelsmann
- Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Department of Sensors and Measurement Technology, 30167 Hannover, Germany
| | - Stefan Zimmermann
- Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Department of Sensors and Measurement Technology, 30167 Hannover, Germany
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Smith BL, Boisdon C, Young IS, Praneenararat T, Vilaivan T, Maher S. Flexible Drift Tube for High Resolution Ion Mobility Spectrometry (Flex-DT-IMS). Anal Chem 2020; 92:9104-9112. [PMID: 32479060 PMCID: PMC7467419 DOI: 10.1021/acs.analchem.0c01357] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
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This paper describes,
in detail, the development of a novel, low-cost,
and flexible drift tube (DT) along with an associated ion mobility
spectrometer system. The DT is constructed from a flexible printed
circuit board (PCB), with a bespoke “dog-leg” track
design, that can be rolled up for ease of assembly. This approach
incorporates a shielding layer, as part of the flexible PCB design,
and represents the minimum dimensional footprint conceivable for a
DT. The low thermal mass of the polyimide substrate and overlapping
electrodes, as afforded by the dog-leg design, allow for efficient
heat management and high field linearity within the tube–achieved
from a single PCB. This is further enhanced by a novel double-glazing
configuration which provides a simple and effective means for gas
management, minimizing thermal variation within the assembly. Herein,
we provide a full experimental characterization of the flexible DT
ion mobility spectrometer (Flex-DT-IMS) with corresponding electrodynamic
(Simion 8.1) and fluid dynamic (SolidWorks) simulations. The Flex-DT-IMS
is shown to have a resolution >80 and a detection limit of low
nanograms
for the analysis of common explosives (RDX, PETN, HMX, and TNT).
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Affiliation(s)
- Barry L Smith
- Department of Electrical Engineering & Electronics, University of Liverpool, Liverpool L69 3GJ, U.K
| | - Cedric Boisdon
- Department of Electrical Engineering & Electronics, University of Liverpool, Liverpool L69 3GJ, U.K
| | - Iain S Young
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 3BX, U.K
| | - Thanit Praneenararat
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Tirayut Vilaivan
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Simon Maher
- Department of Electrical Engineering & Electronics, University of Liverpool, Liverpool L69 3GJ, U.K
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Kirk AT, Kueddelsmann MJ, Bohnhorst A, Lippmann M, Zimmermann S. Improving Ion Mobility Spectrometer Sensitivity through the Extended Field Switching Ion Shutter. Anal Chem 2020; 92:4838-4847. [DOI: 10.1021/acs.analchem.9b04259] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Ansgar T. Kirk
- Department of Sensors and Measurement Technology, Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstrasse 9A, 30167 Hannover, Germany
| | - Maximilian J. Kueddelsmann
- Department of Sensors and Measurement Technology, Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstrasse 9A, 30167 Hannover, Germany
| | - Alexander Bohnhorst
- Department of Sensors and Measurement Technology, Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstrasse 9A, 30167 Hannover, Germany
| | - Martin Lippmann
- Department of Sensors and Measurement Technology, Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstrasse 9A, 30167 Hannover, Germany
| | - Stefan Zimmermann
- Department of Sensors and Measurement Technology, Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Appelstrasse 9A, 30167 Hannover, Germany
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Bunert E, Berger M, Kirk AT, Zimmermann S. Non-radioactive electron source with nanosecond pulse modulation for atmospheric pressure chemical ionization. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:113306. [PMID: 31779458 DOI: 10.1063/1.5126507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/18/2019] [Indexed: 06/10/2023]
Abstract
Ion mobility spectrometers (IMSs) are well-known instruments for fast and ultrasensitive trace gas detection. In recent years, we introduced a compact nonradioactive electron source providing a defined current of free electrons with high kinetic energy at atmospheric pressure for initiating a chemical gas phase ionization of the analytes identical to radioactive sources. Besides its nonradioactivity, one major advantage of this electron source is its controlled electron emission current even in pulsed mode. By optimizing the geometric parameters and developing faster control electronics, we now achieve electron pulses with extremely short pulse widths down to 23 ns. This allows us to kinetically control the formation of reactants and analyte ions by chemical gas phase ionization (e.g., reducing discrimination processes caused by competing ionization), enhancing the analytical performance of the IMS. However, this paper concentrates on the pulsed electron source. For its characterization, we developed a measurement setup, which allows the detection of nanosecond electron pulses with amplitudes of only a few nanoamperes. Furthermore, we investigated the spatial ion distribution in the ionization region depending on several operating parameters, such as the kinetic electron energy or the ionization time.
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Affiliation(s)
- Erik Bunert
- Department of Sensors and Measurement Technology, Institute of Electrical Engineering and Measurement Technology, Leibniz University Hannover, Appelstr. 9A, 30167 Hannover, Germany
| | - Marc Berger
- Department of Sensors and Measurement Technology, Institute of Electrical Engineering and Measurement Technology, Leibniz University Hannover, Appelstr. 9A, 30167 Hannover, Germany
| | - Ansgar T Kirk
- Department of Sensors and Measurement Technology, Institute of Electrical Engineering and Measurement Technology, Leibniz University Hannover, Appelstr. 9A, 30167 Hannover, Germany
| | - Stefan Zimmermann
- Department of Sensors and Measurement Technology, Institute of Electrical Engineering and Measurement Technology, Leibniz University Hannover, Appelstr. 9A, 30167 Hannover, Germany
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