Ammonium quantification in muscovite by infrared spectroscopy

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doi: 10.1016/S0009-2541(02)00420-5
Authors:Busigny, Vincent; Cartigny, Pierre; Philippot, Pascal; Javoy, Marc
Author Affiliations:Primary:
Université Paris VII, Laboratoire de Géochimie des Isotopes Stables, Paris, France
Volume Title:Chemical Geology
Source:Chemical Geology, 198(1-2), p.21-31. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0009-2541
Publication Date:2003
Note:In English. Inst. Phys. Globe de Paris, Contrib. No. 1855; CNRS Contrib. No. 328. 34 refs.; illus., incl. 3 tables
Summary:Single muscovite grains of different chemical composition (in particular Si-content from 3.05 to 3.69 per formulae unit (pfu)) and origin (metamorphic and granitic rocks) were analysed by infrared (IR) spectroscopy. Their ammonium concentrations were subsequently measured by capacitance manometry after extraction as N2 using a sealed-tube combustion technique. The values range from 0 to 2203 ppm NH4+. Correlation between ammonium concentration and ammonium IR absorbance corresponding to NH4+ bending permits an assessment of the ammonium molecular absorptivity at 1430 cm-1N-H1430 = 462±32 l mol-1 cm-1). In order to avoid uncertainties on thickness estimates using an optical technique, a relationship between sample thickness and IR absorbance was determined. Ammonium concentration of muscovite can be directly derived from its IR spectrum using the relationship [NH4+] (ppm) = 1142.5×[(AN-H1430-A2514)/(A1282-A2514)]-606 where A1282, AN-H1430 and A2514 are absorbances corresponding to wavenumbers 1282 (Si-O vibration peak), 1430 (NH4+ bending) and 2514 cm-1 (silicate network vibration), respectively. The precision of ammonium concentration estimates using this method is better than 20% (2σ) for muscovites thicker than 30 µm. This is independent of mineral composition, thus implying that the ammonium concentration vs. IR absorbance relationship is independent of the muscovite-celadonite solid solution. Abstract Copyright (2003) Elsevier, B.V.
Sections:Mineral data
Subjects:Ammonium ion; Concentration; Experimental studies; FTIR spectra; Geochemistry; Granites; Igneous rocks; Infrared spectra; Metamorphic rocks; Mica group; Muscovite; Natural materials; Nitrogen; Phengite; Plutonic rocks; Schists; Sheet silicates; Silicates; Spectra; Alps; Armorican Massif; Asia; Central Europe; China; Dabie Mountains; Europe; Far East; France; Italy; Southern Europe; Switzerland; Western Europe
Abstract Numbers:03M/4504
Record ID:2003047668
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands
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