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On the potential of Raman‐spectroscopy‐based carbonate mass spectrometry
Author(s) -
McKay Nicholas P.,
Dettman David L.,
Downs Robert T.,
Overpeck Jonathan T.
Publication year - 2013
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4218
Subject(s) - raman spectroscopy , analytical chemistry (journal) , chemistry , carbonate , stable isotope ratio , isotope ratio mass spectrometry , isotope , calcite , mass spectrometry , isotopes of carbon , crystal (programming language) , isotopes of oxygen , oxygen 18 , mineralogy , nuclear chemistry , total organic carbon , environmental chemistry , chromatography , physics , organic chemistry , quantum mechanics , computer science , optics , programming language
The potential for using Raman spectroscopy to measure stable oxygen isotope ratios ( 18 O/ 16 O) in carbonates is evaluated by measuring the Raman spectra and isotope ratios of a suite of 60 synthesized, 18 O‐enriched calcite crystals ranging in composition from natural abundance (0.2 mole‐% 18 O) to 1.2 mole‐% 18 O. We determined the Raman‐inferred isotopic ratios (R Raman ) by fitting curves to the ν 1 symmetric stretching peak at 1086 cm −1 and the smaller satellite peak, associated with the ν 1 stretching mode of singly substituted carbonate groups (C 16 O 2 18 O) at 1065 cm −1 . The ratio of the two peak areas shows a 1:1 correspondence with the 18 O/ 16 O ratios derived from standard mass spectrometry methods, confirming that the relative intensities of the ν 1 symmetric stretching peaks is a direct measure of the isotopic ratio in the carbonates. The 1‐sigma uncertainties of the R Raman values of the individual crystals were 0.00079 (384‰ PDB) and 0.00043 (210‰ PDB) for the four‐crystal sample means. This level of uncertainty is much too high to provide significant estimates of natural variability; however, there are multiple prospects for improving the accuracy and precision of the technique. Carbon isotope ratios in carbonates cannot be measured by our approach, but our results highlight the potential of Raman‐based isotope ratio measurement for C and other elements in minerals and organic compounds. Copyright © 2012 John Wiley & Sons, Ltd.