10:15 〜 10:30
[PPS07-06] Discovery of CHNOS molecules in asteroid Ryugu by two-dimensional gas chromatography/time-of-flight mass spectrometry
キーワード：リュウグウ、有機硫黄化合物、可溶性有機分子、GC×GC-TOFMS、はやぶさ２
Japan Aerospace Exploration Agency (JAXA) ‘s Hayabusa2 mission delivered asteroidal sample from the Carbonaceous(C)-type near-Earth asteroid (162173) Ryugu [1]. The Hayabusa2 spacecraft carried out two touchdown operations to sample Ryugu, the first touchdown collected surface asteroid materials, and the second touchdown collected the subsurface materials after the Small Carry-on Impactor (SCI) operation created an artificial crater of >10 m in diameter and 1.7 m of deep from the initial surface on Ryugu using a copper projectile [2].
The organic chemical analysis of Ryugu sample revealed the presence of a wide variety of soluble organic molecules (SOM). They include amino acids, nucleobases, organic acids, and hydrocarbons, etc. [e.g., 3-9]. The analysis of the SOM by the Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR/MS) further illustrated the remarkable molecular diversity of Ryugu’s SOM [6]. One notable feature of Ryugu’s SOM is the sulfur-containing molecular species make up a large proportion of the total molecules detected. In contrasts to the nitrogen-rich chemistry of B-type asteroid (101955) Bennu, a sample returned by the National Aeronautics and Space Administration (NASA)’s OSIRIS-REx mission [10]. Although there are numbers of sulfur-containing molecules present in Ryugu, most of the molecular structures are not well understood. The organosulfur species detected in Ryugu are n-alkylsulfonates, alkylthiosulfonates, hydroxyalkyl-sulfonates, and hydroxyalkylthiosulfonates in a water extract and cyclic sulfur compounds (i.e., S6, S7, S8) and sulfides in organic solvent-extracts [7-9]. The FT-ICR/MS analysis suggested the presence of the diverse CHNOS molecules, which contain both sulfur and nitrogen, yet their exact molecular identities remain unknown.
The purpose of the study is to investigate the characteristic of the organosulfur compounds, especially CHNOS molecules in Ryugu. Thus, we performed non-targeted analysis of the two Ryugu aggregate samples (A0106 & C0107), which were extracted with dichloromethane/methanol (the extract #8 in [3]) by using the two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC×GC-TOFMS). We found that many organosulfur compounds including CHNOS, CHNS, CHOS, and CHS molecules present in the dichloromethane/methanol extract of both two Ryugu samples. Among them, we identified CHNOS and CHNS molecules including benzenesulfonamide and benzothiazolone, using commercially available standards. The benzenesulfonamide consists of a benzene ring, a sulfonyl group (-SO2-) and an amino group. The benzothiazole is a fusion ring of a five-membered heterocyclic ring containing S and N and a benzene ring. Some of the other organosulfur compounds detected also contain a sulfonyl group (-SO2), indicating that the sulfonyl group (-SO2) is one of the main carriers of S in Ryugu. Therefore, we suggest that the organic sulfonic acid would have played an important role in the formation of the diverse organosulfur compounds including CHNOS molecules by aqueous alteration on Ryugu.
References: [1] Tachibana S. et al. (2023) Science 375, 1101–1016. [2] Arakawa et al. (2020) Science 368, 67–71. [3] Naraoka H. et al. (2023) Science 379, 6634. [4] Zeichner S. S. et al. (2023) Science 382, 1411–1416. [5] Oba Y. et al. (2023) Nature Comm. 14, 1292. [6] Schmitt-Kopplin P. et al. (2023) Nature Comm. 14, 6525. [7] Yoshimura T. et al. (2023) Nature Comm. 14, 5284. [8] Aponte J. C. et al. (2023) Earth Planet Space 75, 28. [9] Takano Y. et al. (2024) Nature Comm. 15, 5708. [10] Glavin et al. (2025) Nature Astron. https://doi.org/10.1038/s41550-024-02472-9
The organic chemical analysis of Ryugu sample revealed the presence of a wide variety of soluble organic molecules (SOM). They include amino acids, nucleobases, organic acids, and hydrocarbons, etc. [e.g., 3-9]. The analysis of the SOM by the Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR/MS) further illustrated the remarkable molecular diversity of Ryugu’s SOM [6]. One notable feature of Ryugu’s SOM is the sulfur-containing molecular species make up a large proportion of the total molecules detected. In contrasts to the nitrogen-rich chemistry of B-type asteroid (101955) Bennu, a sample returned by the National Aeronautics and Space Administration (NASA)’s OSIRIS-REx mission [10]. Although there are numbers of sulfur-containing molecules present in Ryugu, most of the molecular structures are not well understood. The organosulfur species detected in Ryugu are n-alkylsulfonates, alkylthiosulfonates, hydroxyalkyl-sulfonates, and hydroxyalkylthiosulfonates in a water extract and cyclic sulfur compounds (i.e., S6, S7, S8) and sulfides in organic solvent-extracts [7-9]. The FT-ICR/MS analysis suggested the presence of the diverse CHNOS molecules, which contain both sulfur and nitrogen, yet their exact molecular identities remain unknown.
The purpose of the study is to investigate the characteristic of the organosulfur compounds, especially CHNOS molecules in Ryugu. Thus, we performed non-targeted analysis of the two Ryugu aggregate samples (A0106 & C0107), which were extracted with dichloromethane/methanol (the extract #8 in [3]) by using the two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC×GC-TOFMS). We found that many organosulfur compounds including CHNOS, CHNS, CHOS, and CHS molecules present in the dichloromethane/methanol extract of both two Ryugu samples. Among them, we identified CHNOS and CHNS molecules including benzenesulfonamide and benzothiazolone, using commercially available standards. The benzenesulfonamide consists of a benzene ring, a sulfonyl group (-SO2-) and an amino group. The benzothiazole is a fusion ring of a five-membered heterocyclic ring containing S and N and a benzene ring. Some of the other organosulfur compounds detected also contain a sulfonyl group (-SO2), indicating that the sulfonyl group (-SO2) is one of the main carriers of S in Ryugu. Therefore, we suggest that the organic sulfonic acid would have played an important role in the formation of the diverse organosulfur compounds including CHNOS molecules by aqueous alteration on Ryugu.
References: [1] Tachibana S. et al. (2023) Science 375, 1101–1016. [2] Arakawa et al. (2020) Science 368, 67–71. [3] Naraoka H. et al. (2023) Science 379, 6634. [4] Zeichner S. S. et al. (2023) Science 382, 1411–1416. [5] Oba Y. et al. (2023) Nature Comm. 14, 1292. [6] Schmitt-Kopplin P. et al. (2023) Nature Comm. 14, 6525. [7] Yoshimura T. et al. (2023) Nature Comm. 14, 5284. [8] Aponte J. C. et al. (2023) Earth Planet Space 75, 28. [9] Takano Y. et al. (2024) Nature Comm. 15, 5708. [10] Glavin et al. (2025) Nature Astron. https://doi.org/10.1038/s41550-024-02472-9