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A proposed mechanism of action of permanent modifiers for molecular absorption spectrometry: the case of calcium monofluoride

  • High-Resolution Continuum Source Molecular Absorption Spectrometry (HR-CS-MAS) with graphite furnace atomizers has been successfully used for the analytical determination of non-metals. The use of permanent modifiers (or coatings) for molecule formation is necessary, but their mechanisms of action remain unclear. In order to understand and improve the current analytical methods, we present a comprehensive mechanistic study of molecule formation in graphite furnaces: a key step into the recovery of analytical signals. Therefore, a well-known system for fluorine determination was studied: the molecule formation of CaF, with Zr as permanent modifier. Through a kinetic approach, an Arrhenius plot showed a pseudo first order reaction respect to F-. By spectroscopic methods (XPS, XAS, EDX) it was possible to elucidate an intermediate state. Here a mechanism is proposed, where ZrO2 works as heterogeneous catalyst: after a pyrolytic step, it is activated to the intermediate state of ZrO(OCaF)High-Resolution Continuum Source Molecular Absorption Spectrometry (HR-CS-MAS) with graphite furnace atomizers has been successfully used for the analytical determination of non-metals. The use of permanent modifiers (or coatings) for molecule formation is necessary, but their mechanisms of action remain unclear. In order to understand and improve the current analytical methods, we present a comprehensive mechanistic study of molecule formation in graphite furnaces: a key step into the recovery of analytical signals. Therefore, a well-known system for fluorine determination was studied: the molecule formation of CaF, with Zr as permanent modifier. Through a kinetic approach, an Arrhenius plot showed a pseudo first order reaction respect to F-. By spectroscopic methods (XPS, XAS, EDX) it was possible to elucidate an intermediate state. Here a mechanism is proposed, where ZrO2 works as heterogeneous catalyst: after a pyrolytic step, it is activated to the intermediate state of ZrO(OCaF) and at higher temperatures, CaF(g) is released from the zirconium-coated graphite surface. With this analytical information, improved surface modifications and coatings for graphite furnaces can be designed and some of them, for example with Zr nanoparticle and Zr xerogels are here presented.zeige mehrzeige weniger

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Metadaten
Autor*innen:Carlos Enrique Abad AndradeORCiD
Koautor*innen:Ana de Oliveira Guilherme Buzanich, Martin Radtke, Andreas Lippitz, Sigrid Benemann, Hans-Joachim Heinrich, Sebastian Recknagel, Norbert Jakubowski, M.-D. Huang, S. Florek, H. Becker-Ross
Dokumenttyp:Vortrag
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2017
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Freie Schlagwörter:Coating; Fluorine; HR-CS-MAS; High-resolution continuum source Molecular Absorption Spectrometry; Modifier; Zirconium oxide
Veranstaltung:ANAKON 2017
Veranstaltungsort:Tübingen, Germany
Beginndatum der Veranstaltung:03.04.2017
Enddatum der Veranstaltung:06.04.2017
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:21.04.2017
Referierte Publikation:Nein
Eingeladener Vortrag:Nein
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