Research Units

Environmental Impacts of Ionic Solutes

Ions play an important role in the environment. Ions are one of the key for the global elemental cycles and observed in marine, soil, river/lake, atmosphere, and living cells. Furthermore, the role of ions is strongly dependent on the chemical forms. In this research unit, we are investigating the roles of ions in environments with the following approach:
(a) Development of universal detection for ionic solutes
(b) Development of on-site analyzers for speciation analysis of trace elements
(c) Investigation of the ionic solutes released from cells.

The unit consists of four members from China, United States of America and Kumamoto University, Japan. We will collaborate strongly to achieve these investigations.

Unit members

  • Japan
    Unit coordinator
    Shin-Ichi OHIRA
    Professor, Faculty of Advanced Science and Technology, Kumamoto University
  • China
    Jian MA
    Professor, College of the Environment and Ecology, Xiamen University
  • USA
    C. Phillip SHELOR
    Assistant Research Professor, Department of Chemistry and Biochemistry, University of Texas at Arlington
  • Japan
    Yuta NAKASHIMA Website
    Associate Professor, Research Field of Bioengineering, Division of Biomedical Engineering, Faculty of Advanced Science and Technology, Kumamoto University




  • Y. Sugo, R. Miyachi, S. Obata, Y. Maruyama, H. Manabe, M. Mori*, N.S. Ishioka, K. Toda, S. Ohira*, Rapid Flow-Based System for Separation of Radioactive Metals by Selective Complex Formation, Analytical Chemistry (IF 6.785), 93, 17069-17075 (2021)
  • S. Ohira*, Y. Sato, K. Horiuchi, C.P. Shelor, and K. Toda, Indirect Potentiometric pH Detection of Weak Acids with Absolute Quantitation by a Theoretical Approach, Analytical Chemistry (IF 6.785), 93, 12305-12311 (2021)
  • K. Owen, K. Saeki, J.D. Warren, A. Bocconcelli, D.N. Wiley, S. Ohira, A. Bombosch, K. Toda, D.P. Zitterbart, Natural Dimethyl Sulfide Gradients would Lead Marine Predators to Higher Prey Biomass, Communications Biology (IF 5.489), 4, 149 (2021).
  • K. Saeki, K. Ikari, Y. Kazuyaa, H. Yokoi, S. Ohira, H. Okochi, K. Toda, Biogenic Diamines and Their Amide Derivatives Are Present in the Forest Atmosphere and May Play a Role in Particle Formation, ACS Earth and Space Chemistry (IF 3.475), 6, 421–430 (2022).
  • Y. Nakashima*, M. Akaike, M. Kounoura, K. Hayashi, K. Morita, Y. Oki, Y. Nakanishi, Evaluation of Osteoblastic Cell Behavior upon Culture on Titanium Substrates Photo-functionalized by Vacuum Ultra-Violet Treatment, Experimental Cell Research (IF 3.905), 410, 112944, (2022)
  • S. Fukuyama, S. Kumamoto, S. Nagano, S. Hitotsuya, K. Yasuda, Y. Kitamura, M. Iwatsuki, H. Baba, T. Ihara, Y. Nakanishi, and Y. Nakashima*, Detection of cancer cells in whole blood using a dynamic deformable microfilter and a nucleic acid aptamer, Talanta (IF 6.057), 228, 122239 (2021).
  • Y. Sugo, R. Miyachi, Y. Maruyama, S. Ohira*, M. Mori*, N.S. Ishioka, K. Toda, Electrodialytic Handling of Radioactive Metal Ions for Preparation of Tracer Reagents, Analytical Chemistry, 92, 14953–14958 (2020). [Cover page]
  • K. Abe, K. Shimohira, Y. Miki, Y. Hirose, S. Ohira, Kei Toda*, Measurement Device for Ambient Carbonyl Sulfide by Means of Catalytic Reduction Followed by Wet Scrubbing/Fluorescence Detection, ACS Omega, 5, 25704–25711 (2020).
  • S. Ohira*, T. Sakaki, R. Miyachi, A. Otsubo, A. Umemoto, Y. Kuwahara, K. Toda, Miniaturized Crossflow Ion Transfer Device for Post-column Enrichment in Ion Chromatography, Talanta, 216, 120989 (2020).
  • M. Taira, K. Sakakibara, K. Saeki, S. Ohira, K. Toda*, Determination of Oxoanions and Water-soluble Species of Arsenic, Selenium, Antimony, Vanadium, and Chromium Eluted in Water from Airborne Fine Particles (PM2.5): Effect of Acid and Transition Metal Content of Particles on Heavy Metal Elution, Environmental Science: Processes and Impacts, 22, 1514–1524 (2020).
  • W.C. Nugraha, H. Nagai, S. Ohira*, K. Toda, Semi-Continuous Monitoring of Cr(VI) and Cr(III) during a Soil Extraction Process by Means of an Ion Transfer Device and Graphite Furnace Atomic Absorption Spectroscopy, Analytical Sciences, 36, 617–620 (2020).
  • S. Kumamoto, K. Nakatake, S. Fukuyama, K. Yasuda, Y. Kitamura, M. Iwatsuki, H. Baba, T. Ihara, Y. Nakanishi, Y. Nakashima*, A dynamically deformable microfilter for selective separation of specific substances in microfluidics, Biomicrofluidics, 14, 064113, 2020.
  • S..Ohira, KAKENHI, Grant-in-Aid for Scientific Research (B) as representative, 2021–2023FY 4,550 kJPY for 2021
  • S. Ohira, KAKENHI, Grant-in-Aid for Scientific Research (B) as collaborator, 2020 – 2023FY 780k JPY for 2021
  • S. Ohira, Adaptable and Seamless Technology transfer Program through targetdriven R&D (A-STEP), 2021FY 3,000 kJPY.
  • S. Ohira, Collaborative study with four companies, total 3,800 kJPY for 2021.
  • S. Ohira, New Energy and Industrial Technology Development Organization (NEDO) JPNP20004 as representative, 2021-2022FY 0 JPY for 2021 (10,000 kJPY for 2022).
  • Y. Nakashima, KAKENHI, Grant-in-Aid for Scientific Research (B) as representative, 2019–2022FY, 3,120 kJPY for 2021
  • Y. Nakashima, KAKENHI, Grant-in-Aid for Challenging Exploratory Research as representative, 2020–2021FY, 3,185 kJPY for 2021
  • Y. Nakashima, Collaborative study with three companies, total 3,885 kJPY for 2021.



  • S. Ohira, Patent JP 6836028



On-line meetings

  • Drs Ohira and Ma (July 6, 2020): They discussed about the research progress and grant applications
  • Drs Ohira and Ma (Nov. 29, 2020): They discussed about the new research topic, arsenic speciation analysis.
  • Drs Ohira and Shelor (Feb. 1, 2020): They discussed about the computational approach for universal detection.



  • S.Obata, M. Fujiwara, K. Toda, S. Ohira, “Flow analysis by electrodialytic pretreatment and enrichment for Fe(II) in environment”, 57th FIA symposium (On-line), 2021/10/6. [Young poster award]
  • S. Ohira, Electrodialytic Ion Handling for Chromium Speciation Analysis, 4th International Seminar on Chemical Education, 2021/9/15. [Invited lecture]
  • S. Ohira, R. Miyachi, S. Obata, Y. Maruyama, H. Manabe, M. Mori, Y. Sugo, N. Ishioka, “Flow devices for simultaneous separation, enrichment and probe synthesis with radio isotopes”, QST scientific festa 2021, 2021/12/8. [Invited lecture]
  • S. Ohira, W.C. Nugraha, K. Toda, Electrodialytic Speciation Analysis for Chromium Species, Pacifichem 2021, on-line, 2021/12/17.
  • S. Ohira, Y. Sato, K. Kaneda, K. Toda, Universal Detection HPLC for Sugars and Organic acids, Pacifichem 2021, on-line, 2021/12/17.
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