Use of Laser Spectroscopy To Measure the 13C/12C and 18O/16O Compositions of Carbonate Minerals

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• 作者：Shaun L. L. Barker ; Gregory M. Dipple ; Feng Dong ; Douglas S. Baer
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：March 15, 2011
• 年：2011
• 卷：83
• 期：6
• 页码：2220-2226
• 全文大小：785K
• 年卷期：v.83,no.6(March 15, 2011)
• ISSN：1520-6882

文摘

The stable carbon and oxygen isotope compositions of carbonate minerals are utilized throughout the earth and environmental sciences for various purposes. Here, we demonstrate the first application of a prototype instrument, based on off-axis integrated cavity output laser spectroscopy, to measure the carbon and oxygen isotope composition of CO₂ gas evolved from the acidification of carbonate minerals. The carbon and oxygen isotope ratios were recorded from absorption spectra of ¹²C¹⁶O¹⁶O, ¹³C¹⁶O¹⁶O, and ¹²C¹⁶O¹⁸O in the near-infrared wavelength region. The instrument was calibrated using CaCO₃ minerals with known 未¹³C_VPDB and 未¹⁸O_VSMOW values, which had been previously calibrated by isotope ratio mass spectrometry relative to the international isotopic standards NBS 18 and NBS 19. Individual analyses are demonstrated to have internal precision (1 SE) of better than 0.15鈥?for 未¹³C and 0.6鈥?for 未¹⁸O. Analysis of four carbonate standards of known isotopic composition over 2 months, determined using the original instrumental calibration, indicates that analyses are accurate to better than 0.5鈥?for both 未¹³C and 未¹⁸O without application of standard鈭抯ample鈭抯tandard corrections.