14:45 〜 15:00
[MZZ42-04] 多重置換同位体CO2分子分析のための中赤外キャビティリングダウン分光装置の開発
キーワード：多重置換同位体分子、安定同位体、二酸化炭素、レーザー分光
Carbon and oxygen have multiple stable isotopes (12C, 13C, 16O, 17O, and 18O). By precisely analysing the abundance ratios of multiply substituted CO2 molecules, known as clumped isotopologues, it is possible to determine the source of carbon dioxide, estimate the temperature at which carbonates formed in the past (palaeohydrothermal temperature), and so on. Conventionally, isotope ratio mass spectrometry has been used to measure the isotope ratios of light elements. However, precise measurement of the abundance of trace amounts of clumped isotopologues is difficult due to isobaric interferences in the mass spectrum caused by dominant molecules. In contrast, laser absorption spectroscopy determines the concentration of target molecules based on their optical absorption properties, which depend on their isotopic composition. If the absorption lines of the target molecules are selected appropriately, quantitative analysis can be made by distinguishing between isotopic molecules, and the isotopic abundance ratio can be measured with high precision.
In this study, we developed a mid-infrared cavity ring-down spectrometer for clumped isotope analysis of CO2 molecules. Highly sensitive laser absorption spectroscopy using an optical cavity, known as cavity ring-down spectroscopy, in the 4 μm region allows precise measurement of the even week photo-absorption or quantification of low abundance CO2 molecules. We have built a spectrometer combined with a sample injection system. In this setup, the absorption of 12C16O16O, 13C16O16O, 12C16O18O, and 13C16O18O can be measured by frequency scanning of a single quantum cascade laser. The evaluation of the spectral sensitivity and the assessment of the basic analytical performance using test samples will be presented.
Acknowledgements: This work was partially supported by JSPS KAKENHI: Grant-in-Aid for Scientific Research (B) 22H03869, Japan.
In this study, we developed a mid-infrared cavity ring-down spectrometer for clumped isotope analysis of CO2 molecules. Highly sensitive laser absorption spectroscopy using an optical cavity, known as cavity ring-down spectroscopy, in the 4 μm region allows precise measurement of the even week photo-absorption or quantification of low abundance CO2 molecules. We have built a spectrometer combined with a sample injection system. In this setup, the absorption of 12C16O16O, 13C16O16O, 12C16O18O, and 13C16O18O can be measured by frequency scanning of a single quantum cascade laser. The evaluation of the spectral sensitivity and the assessment of the basic analytical performance using test samples will be presented.
Acknowledgements: This work was partially supported by JSPS KAKENHI: Grant-in-Aid for Scientific Research (B) 22H03869, Japan.