SEM-EDXRF study of two chemical modifiers based on platinum and tungsten and their effect on ET-AAS atomization of lead

Citation
Ga. Zachariadis et al., SEM-EDXRF study of two chemical modifiers based on platinum and tungsten and their effect on ET-AAS atomization of lead, MIKROCH ACT, 136(3-4), 2001, pp. 115-122
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
MIKROCHIMICA ACTA
ISSN journal
0026-3672 → ACNP
Volume
136
Issue
3-4
Year of publication
2001
Pages
115 - 122
Database
ISI
SICI code
0026-3672(2001)136:3-4<115:SSOTCM>2.0.ZU;2-H
Abstract
The behavior of two chemical modifiers based on platinum and tungsten, is s tudied in the two parts of this work. At first, the chemical and morphologi cal alterations of these during pyrolysis and atomization stages in electro thermal atomic absorption spectrometry are studied. The compounds were H2Pt Cl6 and Na2WO4. A cylindrical graphite tube was used, and fixed shaped rect angular graphite plates were put inside as platforms to prepare the specime ns. The crystalline formations on the platforms were studied by scanning el ectron microscopy and the energy dispersive X-ray spectra allowed the estim ation of the chemical composition changes of the modifiers and the graphite surface. According to the spectra and the images obtained, both modifiers where found to change their crystalline form at temperatures between 500-12 50 degreesC. Severe corrosion of the graphite surface was observed in case of H2PtCl6 at temperature higher than 750 degreesC, while minor damages wer e observed in case of Na2WO4. In the second part of this work, the efficien cy of these modifiers was tested for maximum loss-free pyrolysis temperatur e and atomization of lead by electrothermal atomic absorption spectrometry. The optimum results, concerning these parameters, obtained for medium conc entration of the modifiers. The effect of each modifier on the atomization signal is discussed, and the optimum concentration of each one is estimated .