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Atmospheric Pressure Dark-Current Argon Discharge Ionization with Comparable Performance to Direct Analysis in Real Time Mass Spectrometry

Herein, a dark-current discharge state created by combining argon flow with a needle electrode in ambient air is described that has an ionization efficiency and mechanism comparable to those of conventional helium direct analysis in real time (DART), without requiring dopants and DART glow discharge...

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Detalles Bibliográficos
Autores principales: Sekimoto, Kanako, Sakakura, Motoshi, Hike, Hiroshi, Kawamukai, Takatomo, Shiota, Teruhisa, Takayama, Mitsuo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Mass Spectrometry Society of Japan 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6861550/
https://www.ncbi.nlm.nih.gov/pubmed/31840015
http://dx.doi.org/10.5702/massspectrometry.A0075
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author Sekimoto, Kanako
Sakakura, Motoshi
Hike, Hiroshi
Kawamukai, Takatomo
Shiota, Teruhisa
Takayama, Mitsuo
author_facet Sekimoto, Kanako
Sakakura, Motoshi
Hike, Hiroshi
Kawamukai, Takatomo
Shiota, Teruhisa
Takayama, Mitsuo
author_sort Sekimoto, Kanako
collection PubMed
description Herein, a dark-current discharge state created by combining argon flow with a needle electrode in ambient air is described that has an ionization efficiency and mechanism comparable to those of conventional helium direct analysis in real time (DART), without requiring dopants and DART glow discharge. Using this method, polar compounds such as α-amino acids were ionized in the dark-current argon discharge via (de)protonation, molecular anion formation, fragmentation, (de)protonation with the attachment of oxygen, deprotonation with hydrogen loss and negative ion attachment. In contrast, nonpolar compounds (e.g., n-alkanes) were detected as positive ions via hydride abstraction and oxidation. Major background ions observed were H(3)O(+)(H(2)O)(n), O(2)(·+), O(2)(·−)(H(2)O)(n) and CO(3)(·−). These results indicate that the present dark-current discharge efficiently generates resonance-state argon with an internal energy of ∼14.2 eV, higher than that of the well-known metastable state (∼11.6 eV). It is therefore suggested that ionization reactions occurring there can be attributed to the Penning ionization of atmospheric H(2)O and O(2) by resonance-state argon, analogous to helium DART.
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spelling pubmed-68615502019-12-13 Atmospheric Pressure Dark-Current Argon Discharge Ionization with Comparable Performance to Direct Analysis in Real Time Mass Spectrometry Sekimoto, Kanako Sakakura, Motoshi Hike, Hiroshi Kawamukai, Takatomo Shiota, Teruhisa Takayama, Mitsuo Mass Spectrom (Tokyo) Original Article Herein, a dark-current discharge state created by combining argon flow with a needle electrode in ambient air is described that has an ionization efficiency and mechanism comparable to those of conventional helium direct analysis in real time (DART), without requiring dopants and DART glow discharge. Using this method, polar compounds such as α-amino acids were ionized in the dark-current argon discharge via (de)protonation, molecular anion formation, fragmentation, (de)protonation with the attachment of oxygen, deprotonation with hydrogen loss and negative ion attachment. In contrast, nonpolar compounds (e.g., n-alkanes) were detected as positive ions via hydride abstraction and oxidation. Major background ions observed were H(3)O(+)(H(2)O)(n), O(2)(·+), O(2)(·−)(H(2)O)(n) and CO(3)(·−). These results indicate that the present dark-current discharge efficiently generates resonance-state argon with an internal energy of ∼14.2 eV, higher than that of the well-known metastable state (∼11.6 eV). It is therefore suggested that ionization reactions occurring there can be attributed to the Penning ionization of atmospheric H(2)O and O(2) by resonance-state argon, analogous to helium DART. The Mass Spectrometry Society of Japan 2019 2019-10-25 /pmc/articles/PMC6861550/ /pubmed/31840015 http://dx.doi.org/10.5702/massspectrometry.A0075 Text en Copyright © 2019 Kanako Sekimoto, Motoshi Sakakura, Hiroshi Hike, Takatomo Kawamukai, Teruhisa Shiota, and Mitsuo Takayama. http://creativecommons.org/licenses/by/2.5/ This is an open access article distributed under the terms of Creative Commons Attribution License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
spellingShingle Original Article
Sekimoto, Kanako
Sakakura, Motoshi
Hike, Hiroshi
Kawamukai, Takatomo
Shiota, Teruhisa
Takayama, Mitsuo
Atmospheric Pressure Dark-Current Argon Discharge Ionization with Comparable Performance to Direct Analysis in Real Time Mass Spectrometry
title Atmospheric Pressure Dark-Current Argon Discharge Ionization with Comparable Performance to Direct Analysis in Real Time Mass Spectrometry
title_full Atmospheric Pressure Dark-Current Argon Discharge Ionization with Comparable Performance to Direct Analysis in Real Time Mass Spectrometry
title_fullStr Atmospheric Pressure Dark-Current Argon Discharge Ionization with Comparable Performance to Direct Analysis in Real Time Mass Spectrometry
title_full_unstemmed Atmospheric Pressure Dark-Current Argon Discharge Ionization with Comparable Performance to Direct Analysis in Real Time Mass Spectrometry
title_short Atmospheric Pressure Dark-Current Argon Discharge Ionization with Comparable Performance to Direct Analysis in Real Time Mass Spectrometry
title_sort atmospheric pressure dark-current argon discharge ionization with comparable performance to direct analysis in real time mass spectrometry
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6861550/
https://www.ncbi.nlm.nih.gov/pubmed/31840015
http://dx.doi.org/10.5702/massspectrometry.A0075
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