Nwaboh, Javis A. ; Qu, Zhechao ; Werhahn, Olav ; Ebert, Volker (2024)
Towards an Optical Gas Standard for Traceable Calibration-Free and Direct NO₂ Concentration Measurements.
In: Applied Sciences, 2021, 11 (12)
doi: 10.26083/tuprints-00019526
Artikel, Zweitveröffentlichung, Verlagsversion
 | Es ist eine neuere Version dieses Eintrags verfügbar. |
Kurzbeschreibung (Abstract)
We report a direct tunable diode laser absorption spectroscopy (dTDLAS) instrument developed for NO₂ concentration measurements without chemical pre-conversion, operated as an Optical Gas Standard (OGS). An OGS is a dTDLAS instrument that can deliver gas species amount fractions (concentrations), without any previous or routine calibration, which are directly traceable to the international system of units (SI). Here, we report NO₂ amount fraction quantification in the range of 100–1000 µmol/mol to demonstrate the current capability of the instrument as an OGS for car exhaust gas application. Nitrogen dioxide amount fraction results delivered by the instrument are in good agreement with certified values of reference gas mixtures, validating the capability of the dTDLAS-OGS for calibration-free NO₂ measurements. As opposed to the standard reference method (SRM) based on chemiluminescence detection (CLD) where NO₂ is indirectly measured after conversion to NO, titration with O₃ and the detection of the resulting fluorescence, a dTDLAS-OGS instrument has the benefit of directly measuring NO₂ without distorting or delaying conversion processes. Therefore, it complements the SRM and can perform fast and traceable measurements, and side-by-side calibrations of other NO₂ gas analyzers operating in the field. The relative standard uncertainty of the NO₂ results reported in this paper is 5.1% (k = 1, which is dominated (98%) by the NO₂ line strength), the repeatability of the results at 982.6 µmol/mol is 0.1%, the response time of the instrument is 0.5 s, and the detection limit is 825 nmol/mol at a time resolution of 86 s.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2024 |
| Autor(en): | Nwaboh, Javis A. ; Qu, Zhechao ; Werhahn, Olav ; Ebert, Volker |
| Art des Eintrags: | Zweitveröffentlichung |
| Titel: | Towards an Optical Gas Standard for Traceable Calibration-Free and Direct NO₂ Concentration Measurements |
| Sprache: | Englisch |
| Publikationsjahr: | 15 Januar 2024 |
| Ort: | Darmstadt |
| Publikationsdatum der Erstveröffentlichung: | 2021 |
| Ort der Erstveröffentlichung: | Basel |
| Verlag: | MDPI |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Applied Sciences |
| Jahrgang/Volume einer Zeitschrift: | 11 |
| (Heft-)Nummer: | 12 |
| Kollation: | 10 Seiten |
| DOI: | 10.26083/tuprints-00019526 |
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/19526 |
| Zugehörige Links: | |
| Herkunft: | Zweitveröffentlichung DeepGreen |
| Kurzbeschreibung (Abstract): | We report a direct tunable diode laser absorption spectroscopy (dTDLAS) instrument developed for NO₂ concentration measurements without chemical pre-conversion, operated as an Optical Gas Standard (OGS). An OGS is a dTDLAS instrument that can deliver gas species amount fractions (concentrations), without any previous or routine calibration, which are directly traceable to the international system of units (SI). Here, we report NO₂ amount fraction quantification in the range of 100–1000 µmol/mol to demonstrate the current capability of the instrument as an OGS for car exhaust gas application. Nitrogen dioxide amount fraction results delivered by the instrument are in good agreement with certified values of reference gas mixtures, validating the capability of the dTDLAS-OGS for calibration-free NO₂ measurements. As opposed to the standard reference method (SRM) based on chemiluminescence detection (CLD) where NO₂ is indirectly measured after conversion to NO, titration with O₃ and the detection of the resulting fluorescence, a dTDLAS-OGS instrument has the benefit of directly measuring NO₂ without distorting or delaying conversion processes. Therefore, it complements the SRM and can perform fast and traceable measurements, and side-by-side calibrations of other NO₂ gas analyzers operating in the field. The relative standard uncertainty of the NO₂ results reported in this paper is 5.1% (k = 1, which is dominated (98%) by the NO₂ line strength), the repeatability of the results at 982.6 µmol/mol is 0.1%, the response time of the instrument is 0.5 s, and the detection limit is 825 nmol/mol at a time resolution of 86 s. |
| Freie Schlagworte: | gas analysis, laser absorption spectroscopy, dTDLAS, nitrogen dioxide (NO₂), metrology |
| Status: | Verlagsversion |
| URN: | urn:nbn:de:tuda-tuprints-195260 |
| Zusätzliche Informationen: | This article belongs to the Special Issue Diode Laser Spectroscopy – Robust Sensing for Environmental and Industrial Applications |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 530 Physik 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau 600 Technik, Medizin, angewandte Wissenschaften > 660 Technische Chemie |
| Fachbereich(e)/-gebiet(e): | 16 Fachbereich Maschinenbau 16 Fachbereich Maschinenbau > Fachgebiet Reaktive Strömungen und Messtechnik (RSM) |
| Hinterlegungsdatum: | 15 Jan 2024 13:35 |
| Letzte Änderung: | 16 Jan 2024 07:28 |
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| Suche nach Titel in: | TUfind oder in Google |
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