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Titolo:
Effect of pH on the measurement of biogenic silica
Autore:
Schluter, M; Rickert, D;
Indirizzi:
GEOMAR Res Ctr Marine Geosci, D-24148 Kiel, Germany GEOMAR Res Ctr Marine Geosci Kiel Germany D-24148 D-24148 Kiel, Germany
Titolo Testata:
MARINE CHEMISTRY
fascicolo: 1-2, volume: 63, anno: 1998,
pagine: 81 - 92
SICI:
0304-4203(199812)63:1-2<81:EOPOTM>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
DEEP-SEA SEDIMENTS; MARINE-SEDIMENTS; DETERMINING OPAL; DISSOLUTION; PRESERVATION; ALUMINUM; WATER; OCEAN;
Keywords:
biogenic silica; analytical methods; opal;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Physical, Chemical & Earth Sciences
Citazioni:
29
Recensione:
Indirizzi per estratti:
Indirizzo: Schluter, M GEOMAR Res Ctr Marine Geosci, Wischhofstr 1-3, D-24148 Kiel, Germany GEOMAR Res Ctr Marine Geosci Wischhofstr 1-3 Kiel Germany D-24148
Citazione:
M. Schluter e D. Rickert, "Effect of pH on the measurement of biogenic silica", MAR CHEM, 63(1-2), 1998, pp. 81-92

Abstract

For investigations of the biogenic silica content of plankton, sediment trap, and sediment samples, alkaline extraction is the most common procedure. Different extraction techniques, with respect to the pH of the leaching agent and the method applied to correct for the release of SiO2, by non-biogenic silica phases as clays or feldspars, are applied. By sequential extraction of marine sediment samples and clay standards with solutions of pH 8 to14, we investigated the sensitivity of these leaching techniques to the pHof the leaching solution. In addition to the dissolved silica concentration, the temporal increase of the dissolved aluminum concentration of the leaching agent was measured. For sediments of low biogenic silica content, theresults are considerably affected by the pH of the leaching agent and relative deviations of more than 300% were observed. Correction by the calculated SiO2/Al2O3 ratios of non-biogenic silica phases had no significant effect on the observed pH dependence. Measurements of samples which exceed similar to 10% biogenic silica are only negligibly affected by the pH of the leaching solution. Based on the pH dependence and investigations of a pure Miocene diatom sample, sequential alkaline extraction with a pH of 12.5 is recommended for the determination of biogenic silica. (C) 1998 Elsevier Science B.V. All rights reserved.

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Documento generato il 30/11/20 alle ore 16:38:10