Japan Geoscience Union Meeting 2016

Presentation information

Oral

Symbol M (Multidisciplinary and Interdisciplinary) » M-TT Technology & Techniques

[M-TT28] Frontiers in Geochemistry : Prospect for geochemistry and cosmochemistry in future

Sun. May 22, 2016 10:45 AM - 12:15 PM A04 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Hajime Obata(Marine inorganic chemistry division, Atmosphere and Ocean Research Institute, University of Tokyo), Hirochika Sumino(Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo), Tetsuya Yokoyama(Department of Earth and Planetary Sciences, Graduate School of Science and Engineering, Tokyo Institute of Technology), Takafumi Hirata(Graduate School of Science, Kyoto University), Urumu Tsunogai(Graduate School of Environmental Studies, Nagoya University), Yoshio Takahashi(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo), Shogo Tachibana(Department of Natural History Scieces, Hokkaido University), Katsuhiko Suzuki(Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology), Gen Shimoda(Geological Survey of Japan, AIST), Hiroyuki Kagi(Geochemical Research Center, Graduate School of Science, University of Tokyo), Yusuke Yokoyama(Atmosphere and Ocean Research Institute, University of Tokyo), Chair:Hirochika Sumino(Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo), Tetsuya Yokoyama, Hajime Obata(Marine inorganic chemistry division, Atmosphere and Ocean Research Institute, University of Tokyo)

11:45 AM - 12:00 PM

[MTT28-11] Application of FTICR-MS analysis to soil organic matter

*Kosuke Ikeya1,3, Rachel L. Sleighter2, Patrick G. Hatcher2, Akira Watanabe3 (1.National Institute for Agro Environmental Sciences, 2.Old Dominion University, 3.Nagoya University)

Keywords:soil organic matter, mass spectrometry

Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) has an ultrahigh resolution which makes it possible that respective organic molecules detected are accurately assigned to a molecular formula. Soil organic matter plays important roles associated with crop productivity and carbon sequestration. However, the chemical structure is still unknown. We applied this technique to some humic and fulvic acids that were chemically extracted and separated from some typical soils in Japan.
Materials and methods
Humic acids (HAs) were prepared from ten Japanese soils to cover varying degrees of humification and fulvic acids (FAs) were prepared from four Japanese and one Chinese soils according to NAGOYA method or IHSS method. The degree of humification of HAs was evaluated with the absorbance at 600 nm per mg C mL-1 (A600/C) and the ratio of absorbances at 400 and 600 nm on a logarithmic scale [log(A400/A600)]. Based on these two variables, HAs were classified into four types: Rp < P < B < A, with the degree of humificaiton increasing in this order. The FTICR-MS was performed according to Sleighter and Hatcher (2008). The molecular formulas assigned were examined using the van Krevelen diagram, double bond equivalent (DBE), and Kendrick mass defect (KMD) analysis that focusing on condensed aromatic structure.
Results
1) The number of molecular formulas in the condensed aromatic region increased from Type Rp (124-374) HAs to Type A HAs (751-1008). The sum of the peak magnitudes of the condensed aromatic components increased with increasing degree of humification.
2) The largest DBE values tended to be larger in the order: Type A (33) > Type B (30) > Type P (27) > Type Rp (25) HAs.
3) The KMD analysis indicated that potential structures of condensed aromatic components having 2-10 rings could occur in the soil HAs. The largest number of the rings increased in the order: Types Rp and P (7) < Type B (9) < Type A (10) HAs.
4) The KMD analysis indicated that potential structures of condensed aromatic components having up to 7 rings could occur in the five FAs.