17:15 〜 18:30
[MTT42-P04] Sub-microgram sulfur isotope analysis for the biological, geological, and extraterrestrial samples by sensitivity-improved EA/IRMS
キーワード：硫黄同位体比、化合物レベル同位体分析、メッシニアン期地中海塩分危機、小惑星リュウグウ、はやぶさ2
The natural isotopic composition of sulfur (δ34S) is a useful, strong tool in geochemistry, ecology, environmental and planetary sciences. However, the scope of application is often limited by analytical capability. In the case of a sulfur isotope as well, it was often limited by analytical requirements for a large sample size (>60 µgS), and complicated preparatory procedures. To achieve precise measurement of δ34S within small and limited quantities of samples, and to expand the scientific applicational range of the tool, we have developed a robust, sensitivity-improved sulfur isotopic analysis system by optimizing a commercial continuous-flow elemental analyzer/isotope-ratio mass spectrometer (EA/IRMS). Our EA/IRMS system successfully reduced the quantity of the required sample to 0.4 µgS or less to obtain reliable data of the sulfur abundances and isotopic compositions. In this presentation, we introduce the overview of the sensitivity-improved EA/IRMS for δ34S with some application results from natural samples, such as gypsum, meteorites, and sulfur-containing organic compound such as methionine from biological samples.
Geological Samples: We established the conventional method to obtain δ34S from gypsums and foraminiferal carbonates, with precisions of ±0.2‰ from samples of 0.5-2 µgS. The method was applied to study the sulfur cycle and evaporite formation during the Messinian Salinity Crisis. We will introduce the method details and the partial results of the project, as the main results will be presented and discussed by Kochi et al. at Session M-IS16 in this meeting.
Extraterrestrial Samples: We will also present the preliminary results of δ34S for carbonaceous chondrites (Murray, Murchison, Yamato 793321). The isotopic composition of bulk sulfur was obtained by analyzing the original (pre-treated) powders and the SOM extracted residues for these samples. The analytical techniques are going to be applied to investigate sample material recovered from the C-type asteroid Ryugu, as part of the Hayabusa2 SOM analysis team objectives [1,2].
Compound-Specific Samples: When combined with the compound-isolation/purification benefits of high-performance liquid chromatography (HPLC), the improved sulfur EA/IRMS can be applied to organic molecules, spanning a wide range of polarities and molecular weights, as well as investigate compound-specific isotope analysis. We will present the obtained δ34S of Methionine separated from natural samples.
References
[1] Ogawa et al. Quantification and Isotopic Measurements of Submicrogram Scales Carbon and Nitrogen from Extraterrestrial Materials Through Nano-EA/IRMS. Lunar and Planetary Science Conference. No. 2326. (2020)
[2] Yoshimura et al. Major and Trace Element Composition in Acid-Soluble Extracts of Murchison and Yamato Meteorites. Lunar and Planetary Science Conference. No. 2326. (2020)
Geological Samples: We established the conventional method to obtain δ34S from gypsums and foraminiferal carbonates, with precisions of ±0.2‰ from samples of 0.5-2 µgS. The method was applied to study the sulfur cycle and evaporite formation during the Messinian Salinity Crisis. We will introduce the method details and the partial results of the project, as the main results will be presented and discussed by Kochi et al. at Session M-IS16 in this meeting.
Extraterrestrial Samples: We will also present the preliminary results of δ34S for carbonaceous chondrites (Murray, Murchison, Yamato 793321). The isotopic composition of bulk sulfur was obtained by analyzing the original (pre-treated) powders and the SOM extracted residues for these samples. The analytical techniques are going to be applied to investigate sample material recovered from the C-type asteroid Ryugu, as part of the Hayabusa2 SOM analysis team objectives [1,2].
Compound-Specific Samples: When combined with the compound-isolation/purification benefits of high-performance liquid chromatography (HPLC), the improved sulfur EA/IRMS can be applied to organic molecules, spanning a wide range of polarities and molecular weights, as well as investigate compound-specific isotope analysis. We will present the obtained δ34S of Methionine separated from natural samples.
References
[1] Ogawa et al. Quantification and Isotopic Measurements of Submicrogram Scales Carbon and Nitrogen from Extraterrestrial Materials Through Nano-EA/IRMS. Lunar and Planetary Science Conference. No. 2326. (2020)
[2] Yoshimura et al. Major and Trace Element Composition in Acid-Soluble Extracts of Murchison and Yamato Meteorites. Lunar and Planetary Science Conference. No. 2326. (2020)