TY - JOUR
T1 - High-Precision Simultaneous 18 O/ 16 O, 13 C/ 12 C, and 17 O/ 16 O Analyses for Microgram Quantities of CaCO 3 by Tunable Infrared Laser Absorption Spectroscopy
AU - Sakai, Saburo
AU - Matsuda, Shinichi
AU - Hikida, Toshihide
AU - Shimono, Akio
AU - Mcmanus, J. Barry
AU - Zahniser, Mark
AU - Nelson, David
AU - Dettman, David L.
AU - Yang, Danzhou
AU - Ohkouchi, Naohiko
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/11/7
Y1 - 2017/11/7
N2 - Stable isotope ratios ( 18 O/ 16 O, 13 C/ 12 C, and 17 O/ 16 O) in carbonates have contributed greatly to the understanding of Earth and planetary systems, climates, and history. The current method for measuring isotopologues of CO 2 derived from CaCO 3 is primarily gas-source isotope ratio mass spectroscopy (IRMS). However, IRMS has drawbacks, such as mass overlap by multiple CO 2 isotopologues and contaminants, the requirement of careful sample purification, and the use of major instrumentation needing permanent installation and a high power electrical supply. Here, we report simultaneous 18 O/ 16 O, 13 C/ 12 C, and 17 O/ 16 O analyses for microgram quantities of CaCO 3 using a tunable mid-infrared laser absorption spectroscopy (TILDAS) system, which has no mass overlap problem and yields high sensitivity/precision measurements on small samples, as small as 0.02 μmol of CO 2 (equivalent to 2 μg of CaCO 3 ) with standard errors of less than 0.08 ‰ for 18 O/ 16 O and 13 C/ 12 C (±0.136 ‰ and ±0.387 ‰ repeatability; n = 10). In larger samples of CO 2 , 0.68 μmol (or 68 μg of CaCO 3 ), standard error is less than 0.04 ‰ for 18 O/ 16 O and 13 C/ 12 C (< ±0.1 ‰ repeatability; n = 10) and 0.03 ‰ for 17 O/ 16 O (±0.069 ‰ repeatability; n = 10). We also show, for the first time, the relationship between 17 O/ 16 O ratios measured using the TILDAS system and published 17 O values of international standard materials (NBS-18 and -19) measured by IRMS. The benchtop TILDAS system, with cryogen-free sample preparation vacuum lines for microgram quantities of carbonates, is therefore a significant advance in carbonate stable isotope ratio geochemistry and is a new alternative to conventional IRMS.
AB - Stable isotope ratios ( 18 O/ 16 O, 13 C/ 12 C, and 17 O/ 16 O) in carbonates have contributed greatly to the understanding of Earth and planetary systems, climates, and history. The current method for measuring isotopologues of CO 2 derived from CaCO 3 is primarily gas-source isotope ratio mass spectroscopy (IRMS). However, IRMS has drawbacks, such as mass overlap by multiple CO 2 isotopologues and contaminants, the requirement of careful sample purification, and the use of major instrumentation needing permanent installation and a high power electrical supply. Here, we report simultaneous 18 O/ 16 O, 13 C/ 12 C, and 17 O/ 16 O analyses for microgram quantities of CaCO 3 using a tunable mid-infrared laser absorption spectroscopy (TILDAS) system, which has no mass overlap problem and yields high sensitivity/precision measurements on small samples, as small as 0.02 μmol of CO 2 (equivalent to 2 μg of CaCO 3 ) with standard errors of less than 0.08 ‰ for 18 O/ 16 O and 13 C/ 12 C (±0.136 ‰ and ±0.387 ‰ repeatability; n = 10). In larger samples of CO 2 , 0.68 μmol (or 68 μg of CaCO 3 ), standard error is less than 0.04 ‰ for 18 O/ 16 O and 13 C/ 12 C (< ±0.1 ‰ repeatability; n = 10) and 0.03 ‰ for 17 O/ 16 O (±0.069 ‰ repeatability; n = 10). We also show, for the first time, the relationship between 17 O/ 16 O ratios measured using the TILDAS system and published 17 O values of international standard materials (NBS-18 and -19) measured by IRMS. The benchtop TILDAS system, with cryogen-free sample preparation vacuum lines for microgram quantities of carbonates, is therefore a significant advance in carbonate stable isotope ratio geochemistry and is a new alternative to conventional IRMS.
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U2 - 10.1021/acs.analchem.7b03582
DO - 10.1021/acs.analchem.7b03582
M3 - Article
C2 - 28937751
AN - SCOPUS:85056283895
SN - 0003-2700
VL - 89
SP - 11846
EP - 11852
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 21
ER -