• Treffer 8 von 53
Zurück zur Trefferliste

Zirconium permanent modifiers for graphite furnaces used in absorption spectrometry: understanding their structure and mechanism of action

  • The mechanism of action of zirconium permanent modifiers on graphite surfaces was investigated in order to understand its influence on the analytical signal in atomic and molecular absorption spectrometry (AAS/MAS). For this, the molecule formation of CaF was studied, which is used for the indirect analytical determination of fluorine in high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). The kinetics of this reaction was established by monitoring its molecular spectrum at different atomisation temperatures. An Arrhenius plot showed a pseudo-first order reaction with respect to fluorine (n = 1). An intermediate state was isolated, and its structure was elucidated by spectroscopic methods: scanning electron microscopy with energy dispersive X-ray spectroscopy (SEMEDX), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XANES and EXAFS), and Raman microspectroscopy. We propose here a mechanism, where ZrO2 acts as aThe mechanism of action of zirconium permanent modifiers on graphite surfaces was investigated in order to understand its influence on the analytical signal in atomic and molecular absorption spectrometry (AAS/MAS). For this, the molecule formation of CaF was studied, which is used for the indirect analytical determination of fluorine in high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). The kinetics of this reaction was established by monitoring its molecular spectrum at different atomisation temperatures. An Arrhenius plot showed a pseudo-first order reaction with respect to fluorine (n = 1). An intermediate state was isolated, and its structure was elucidated by spectroscopic methods: scanning electron microscopy with energy dispersive X-ray spectroscopy (SEMEDX), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XANES and EXAFS), and Raman microspectroscopy. We propose here a mechanism, where ZrO2 acts as a heterogeneous catalyst: after a pyrolytic step, an intermediate state of ZrO(OCaF) is activated, and at higher temperatures, CaF(g) is released from the zirconium-coated graphite surface. No evidence of the formation of zirconium carbide was found. Consequently, as the CaF formation is catalysed by a heterogeneous catalyst, surface modifications with ZrO2 nanoparticles and ZrO xerogels were investigated in order to increase the surface area. Their influence was evaluated in the molecule formation of CaF, CaCl, CaBr, and CaI. Graphite furnace modification with zirconium oxide nanoparticles proves to be the best choice for fluorine analysis with a signal enhancement of more than eleven times with respect a non-coated graphite furnace. However, the influence of zirconium modifications in the analytical signals of Cl, and I is lower than the F signals or even negative in case of the Br. Understanding zirconium modifiers as heterogeneous catalysts offers a new perspective to AAS and MAS, and reveals the potential of surface analytical methods for development of improved permanent modifiers and graphite furnace coatings.zeige mehrzeige weniger

Volltext Dateien herunterladen

  • authorreprints.pdf
    eng
  • Electronic Supplementary Material.pdf
    eng

Metadaten exportieren

Weitere Dienste

Teilen auf Twitter Suche bei Google Scholar
Metadaten
Autoren/innen:Carlos Abad, S. Florek, H. Becker-Ross, M.-D. Huang, Ana Guilherme Buzanich, Martin Radtke, Andreas Lippitz, Vasile-Dan Hodoroaba, Thomas Schmid, Hans-Joachim Heinrich, Sebastian Recknagel, Norbert Jakubowski, Ulrich Panne
Dokumenttyp:Zeitschriftenartikel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Journal of Analytical Atomic Spectrometry
Jahr der Erstveröffentlichung:2018
Organisationseinheit der BAM:P Präsidium
1 Analytische Chemie; Referenzmaterialien
1 Analytische Chemie; Referenzmaterialien / 1.1 Anorganische Spurenanalytik
1 Analytische Chemie; Referenzmaterialien / 1.3 Strukturanalytik
1 Analytische Chemie; Referenzmaterialien / 1.4 Prozessanalytik
1 Analytische Chemie; Referenzmaterialien / 1.6 Anorganische Referenzmaterialien
6 Materialschutz und Oberflächentechnik
6 Materialschutz und Oberflächentechnik / 6.1 Oberflächenanalytik und Grenzflächenchemie
P Präsidium / P.0 Präsident und Vizepräsident
Verlag:Royal Society of Chemistry
Jahrgang/Band:33
Ausgabe/Heft:12
Erste Seite:2034
Letzte Seite:2042
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten
Freie Schlagwörter:Absorption spectrometry; Calcium monofluoride; Graphite furnace; HR-CS-MAS; Nanoparticles; Xerogel; Zirconium
Themenfelder/Aktivitätsfelder der BAM:Material
Material / Materialien und Stoffe
Analytical Sciences
Analytical Sciences / Spurenanalytik und chemische Zusammensetzung
Analytical Sciences / Oberflächen- und Grenzflächenanalytik
Analytical Sciences / Strukturanalytik und Materialographie
DOI:https://doi.org/10.1039/C8JA00190A
URL:https://pubs.rsc.org/en/content/articlelanding/2018/ja/c8ja00190a
URL:http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS_CPL&DestLinkType=FullRecord&UT=WOS:000451536000019
ISSN:0267-9477
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:29.11.2018
Referierte Publikation:Ja
Datum der Eintragung als referierte Publikation:13.12.2018