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Staff

Professor
Hisanori IMURA
imura@se.kanazawa-u.ac.jp
Solvent extraction of metal complexes
Development of novel absolute determination methods
Speciation of environmjental trace elements
Associate Professor
Hirohisa NAGATANI
nagatani@se.kanazawa-u.ac.jp
Spectroelectrochemical study of charge transfer reaction at liquid/liquid interfaces
Assistant Professor
Yoshio NISHIYAMA
yosi1166@se.kanazawa-u.ac.jp   
Development of novel chiroptical analytical measurements   
   

Research

We are focusing on the development of novel analytical methods utilizing liquid/liquid and solid/liquid interfaces. The study covers separation analysis of trace elements in waters by solvent extraction and chromatography, chemical speciation of heavy metals, spectroelectrochemical study of charge transfer mechanism at liquid/liquid interfaces, the development of X-ray absorption spectroscopy at liquid interfaces, and development of functionalized carbonaceous substrates and its application for chemical sensing.

Our current research projects include:
  1. Separation Analysis
  2. Instrumental Analysis
  3. Development of Absolute Determination Method
You can also see complete publication list of our research group.

Separation Analysis

To aim the development of selective separation, enrichment and quantitative analysis method of metal ions and metal complexes, we take a multi-component approach that integrates the use of sterically and hydrophobically designed extractants with controlled coordination and solvation, ionic liquid (IL) chelate extraction system and surfactant-assisted liquid-liquid extraction, and specific interaction and adsorption phenomena at liquid/liquid interfaces. Distribution constants of 2-thenoyltrifluoroacetone (Htta) and its Ni(II)and Cu(II) chelates between 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (CnmimTf2N; n = 4, 6, and 8) as ILs and an aqueous phase were determined. Solvent properties of a series of ILs were evaluated with the aid of the regular solution theory, and so the specific solvation of the Ni(II) chelate with the ILs was revealed by time-resolved laser-induced fluorescence spectroscopy and infrared absorption spectroscopy. A novel synergistic extraction system was investigated for the possible selective separation of light lanthanoids using an IL, C4mimTf2N, as an extraction solvent and Htta and 18-crown-6 as extractants.

Keywords and related papers

Spectroelectrochemical Analysis at Liquid/Liquid Interfaces

The interfacial behavior of ionic dyes at the polarized liquid/liquid interface is studied by spectroelectrochemical techniques. By analyzing the appropriate optical signal instead of the overall current responses, the interfacial behavior of the target dye species could be studied in the absence of the interference with non-chromophoric species. Potential-modulated fluorescence (PMF) spectroscopy has been applied for the ion-transfer reaction across the liquid/liquid interface. The high sensitivity of PMF spectroscopy to interfacial phenomena, especially adsorption, has allowed us to investigate the various fluorescent species, such as porphyrin, xanthene, and pyrene derivatives. Recently, we have demonstrated that a photocurrent arising from the photoreduction of metalloporphyrin is significantly enhanced in the presence of gold nanoparticles (Au-NPs). We further investigate the photoreactivity of metal nanoparticles, e.g. Au-NPs, gold core-silver shell nanoparticles etc., electrochemically adsorbed at the liquid/liquid interface.

Keywords and related papers

Development of chiroptical analysis with surface plasmon resonance

Optical properties for circularly polarized light, typified by circular dichroism and optical rotatory dispersion, are unique to chiral molecule, and consequently have been utilized to analyze chiral proteins and amino acids. We are developing spectroscopic methods to characterize chiroptical properties with higher sensitivity. Surface plasmon resonance (SPR) supported by novel metallic films or nanoparticles enhances the interaction between light and molecule and is promising for sensitive chiroptical characterization. We are investigating the applicability of SPR to the chiroptical characterization by polarization spectroscopy.

Development of Absolute Determination Method

Absolute determination method is an accurate, precise, and quantification method without calibration curves nor comparison standard. Titrimetry, gravimetric analysis, coulometric titration and isotope dilution mass spectrometry are considered as the primary methods of measurement in realizing traceability to SI. We developed a novel absolute determination method using substoichiometric isotope dilution for selective extraction of boric acid. The electrophoretic equilibrium and the chiral separation of D,L-amino acids and phosphorous-containing amino acid were successfully achieved by capillary zone electrophoresis with β- and γ-cycrodextrin as a chiral selector.

Keywords and related papers