| Re-evaluation of linearity and precision of Gas Bench II-IRMS system and potential implications for carbon and oxygen isotope measurements on small-sized carbonate samples |
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| 作者姓名： | Xu WANG Fu S. ZHANG Zhongli DING |
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| 作者单位： | [1]Laboratory for Environmental Isotope Analysis, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China [2]Subdivision of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China |
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| 摘 要： | In this study, the δ^13C and δ^18O values were systematically measured on NBS-18, NBS-19 and IAEA-CO-1 with different sample sizes, with the objective to examine the stability and reproducibility of previously developed linearity correction strategy especially for small-sized samples （e.g. 〈50 μg）. Firstly, the δ^13C and δ^18O values of NBS-19 standards （6-10 samples per run） with sample sizes scattered below -100 μg were determined in three different runs. The logarithmic regressions were performed on the plots of δ-values vs. peak area （sample size） for each run and the correction was applied using peak area of the first peak. Results show that two of the three data sets have almost the same regressive equations for both δ^13C and δ^18O values. The maximum difference in δ^13C values calculated by three equations when sample size varies between -10 and -100 μg is better than 0.15‰, compared with the maximum 0.82‰ for δ^18O values. Since alteration of phosphoric acids could not influence carbon isotope, the 〈0.15‰ difference in calculated δ^13C values should reflect the stability of mass spectrometer conditions. In contrast, the large difference in regressive equations for δ^18O values may be attributed to changed oxygen isotope in phosphoric acids due to exchange with atmosphere through time. It means that standards with sample sizes properly distributed should be arranged in every run for subsequent linearity correction of δ^18O values of small-sized samples （e.g. marine ostracode）.
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| 关 键 词： | 氧 同位素 碳酸盐 线性 稳定性 地球化学 |
Re-evaluation of linearity and precision of Gas Bench II-IRMS system and potential implications for carbon and oxygen isotope measurements on small-sized carbonate samples |
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| Xu WANG Fu S. ZHANG Zhongli DING.Re-evaluation of linearity and precision of Gas Bench II-IRMS system and potential implications for carbon and oxygen isotope measurements on small-sized carbonate samples[J].Chinese Journal of Geochemistry,2006,25(B08):206-206. |
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| Abstract: | |
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| Keywords: | Gas Bench II-IRMS carbon isotope oxygen isotope small-sized carbonate linearity correction |
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