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ERIC Number: EJ1011420
Record Type: Journal
Publication Date: 2013-Jan
Pages: 5
Abstractor: As Provided
Reference Count: 16
ISBN: N/A
ISSN: ISSN-0021-9584
An Exercise on Calibration: DRIFTS Study of Binary Mixtures of Calcite and Dolomite with Partially Overlapping Spectral Features
De Lorenzi Pezzolo, Alessandra
Journal of Chemical Education, v90 n1 p118-122 Jan 2013
Unlike most spectroscopic calibrations that are based on the study of well-separated features ascribable to the different components, this laboratory experience is especially designed to exploit spectral features that are nearly overlapping. The investigated system consists of a binary mixture of two commonly occurring minerals, calcite and dolomite, whose DRIFT (diffuse reflectance infrared Fourier transform) spectra present a peak at about 880 cm-1 due to the C-O out-of-plane bending mode separated by 6 cm-1. Consequently, in the 870-890 cm-1 region of its medium- to low-resolution spectrum, any binary mixture made up of calcite and dolomite gives rise to a single feature due to the superposition of these two peaks. The wavenumbers of the peak center corresponding to mixtures with different composition are shown to be directly proportional to the mixture dolomiticity index, ID, which is related to the mass of dolomite and calcite. The parameters resulting from a linear fit on the measured data for 12 mixtures with ID ranging from 0 to 100 allow the determination of the composition of any binary mixture of calcite/dolomite given the wavenumber of the 870-890 cm-1 peak in the corresponding DRIFT spectrum. This experience can be carried out in a single laboratory period and allows the collection of a spectroscopic data set that can be used in a discussion involving different and more conventional calibration approaches. (Contains 6 figures and 2 tables.)
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail: eic@jce.acs.org; Web site: http://pubs.acs.org/jchemeduc
Publication Type: Journal Articles; Reports - Research
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A