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Lohmayer, Regina ; Reithmaier, Gloria ; Bura-Nakić, Elvira ; Planer-Friedrich, Britta:
Ion-Pair Chromatography Coupled to Inductively Coupled Plasma−Mass Spectrometry (IPC-ICP-MS) as a Method for Thiomolybdate Speciation in Natural Waters.
In: Analytical Chemistry.
Bd. 87
(2015)
Heft 6
.
- S. 3388-3395.
ISSN 1520-6882
DOI: https://doi.org/10.1021/ac5046406
Abstract
Molybdenum precipitates preferentially under reducing conditions; therefore, its occurrence in sediment records is used as an indicator of paleoredox conditions. Although thiomolybdates (MoO4−xSx2− with x = 1−4) supposedly are necessary intermediates in the process of molybdenum precipitation under anoxic conditions, there is no information about their abundance in natural environments,because of a lack of element-specific methods with sufficientlylow detection limits. Here, we optimized ion-pair chromatographicseparation for coupling to an inductively coupledplasma−mass spectrometry detector (IPC-ICP-MS). 2-Propanol(10%−25% gradient) replaced the previously used acetonitrile (25%−75%) as the solvent, to reduce the carbon load into the plasma. In synthetic solutions, formation of thiomolybdates was found to occur spontaneously in the presence of excess sulfide and the degree of thiolation was highest at pH 7. Excess hydroxyl led to a transformation of thiomolybdates to molybdate. Under acidic to neutral conditions, precipitation of molybdenum and hydrolysis of tetrathiomolybdate were observed. Flash-freezing was found to be suitable to stabilize tetrathiomolybdate, with 2 mM) negatively affected the detection of molybdate, which eluted mainly in the dead volume, but had no negative effect on higher thiolated molybdates. Detection limits were ∼10 nM. With the newly developed IPC-ICP-MSmethod, thiomolybdates were found to form spontaneously in euxinic marine waters after adding a molybdate spike and occur naturally in sulfidic geothermal waters.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Zusätzliche Informationen: | BAYCEER127658 |
| Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Geowissenschaften > Professur Umweltgeochemie Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Geowissenschaften > Professur Umweltgeochemie > Professur Umweltgeochemie - Univ.-Prof. Dr. Britta Planer-Friedrich Fakultäten Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Geowissenschaften |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik |
| Eingestellt am: | 03 Mai 2015 08:56 |
| Letzte Änderung: | 14 Nov 2019 09:51 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/12612 |