KINDAI UNIVERSITY


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Hirofumi Kawazumi

Profile

FacultyDepartment of Biological and Environmental Chemistry / Graduate School of Industory
PositionProfessor
Degree
Commentator Guidehttps://www.kindai.ac.jp/meikan/321-kawazumi-hirofumi.html
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Last Updated :2019/06/17

Education and Career

Education

  •  - 1981 , Kyushu University, Graduate School, Division of Integrated Science and Engineering
  •  - 1979 , Kyushu University, Faculty of Science

Academic & Professional Experience

  •   1995 ,  - 2002 , Kinki University, Associate Professor
  •   2002 , - Kinki University, Professor
  •   1991 ,  - 1994 , Kitakyushu University, Associate Professor
  •   1981 ,  - 1990 , Kyushu University, Assistant Professor

Research Activities

Research Areas

  • Science education/Educational technology, Science education
  • Applied Chemistry, Analytical chemistry

Research Interests

  • Laser Analytical Chemistry, Education of Environmental Science, Environmental Analysis

Published Papers

  • Enhanced Photocatalytic Degradation of Methyl Orange by Au/TiO2 Nanoparticles under Neutral and Acidic Solutions, Masaharu Tsuji, Kanako Matsuda, Mayu Tanaka, Satsuki Kuboyama, Keiko Uto, Nozomi Wada, Hirofumi Kawazumi, Takeshi Tsuji, Hiroki Ago, and Jun-ichiro Hayashi, ChemistrySelect, 3, 1432 - 1438, Mar. 2018 , Refereed
  • In situ observation of desorption reaction of cytochrome c from solid/liquid interfaces with slab optical waveguide spectroscopy, Shinya Taguchi, Hirofumi Kawazumi, Toshihiko Nagamura, Hirotaka Okabe, Naoki Matsuda, Analytical Sciences, 33, 461 - 463, Jan. 01 2017
    Summary:© The Japan Society for Analytical Chemistry. An automated solution exchange (SE) mechanism has been introduced to slab optical waveguide spectroscopy to estimate the protein immobilizing ability of a slab optical waveguide (SOWG) surface. In each SE process, SOWG spectral change in absorbance at peak position of cytochrome c (cyt.c) Soret band at 409 nm was observed to analyze the desorption ratio of cyt.c adsorbed on SOWG surface. Continuous SE processes for 100 times have successfully brought us a kind of master desorption curve of cyt.c, which was well fitted by a double exponential equation, indicating the existence of three kinds of adsorbed states, including weakly adsorbed, strongly adsorbed, and immobilized cyt.c. The present results showed that around 30 times SE processes were enough to anticipate the ratio of desorbed and immobilized amounts of cyt.c adsorbed on SOWG surface.
  • Synthesis of Pt-Ag alloy triangular nanoframes by galvanic replacement reactions followed by saturated NaCl treatment in an aqueous solution, Masaharu Tsuji, Masaharu Tsuji, Masaharu Tsuji, Mika Hamasaki, Atsuhiko Yajima, Masashi Hattori, Takeshi Tsuji, Takeshi Tsuji, Hirofumi Kawazumi, Materials Letters, 121, 113 - 117, Apr. 15 2014
    Summary:Pt-Ag alloy triangular nanoframes were prepared by a galvanic replacement (GR) reaction of Ag nanoprisms with H 2 PtCl 6 in an aqueous solution. Their growth mechanisms were studied by observing transmission electron microscopic (TEM) and TEM-energy dispersed X-ray spectroscopy (EDS) images and surface plasmon resonance (SPR) bands. Results show that triangular Pt-Ag alloy prisms are slowly formed 12-48 h after the addition of H 2 PtCl 6 . We found that after treatment using saturated NaCl solution is effective for the transformation of Ag-rich Pt-Ag alloy nanoprisms to Pt-rich Pt-Ag nanoframes. © 2014 Elsevier B.V.
  • Synthesis of Ag-Au and Ag-Pd alloy triangular hollow nanoframes by galvanic replacement reactions without and with post-treatment using NaCl in an aqueous solution, Masaharu Tsuji, Masaharu Tsuji, Masaharu Tsuji, Takafumi Kidera, Atsuhiko Yajima, Mika Hamasaki, Masashi Hattori, Takeshi Tsuji, Takeshi Tsuji, Hirofumi Kawazumi, CrystEngComm, 16, 2684 - 2691, Apr. 07 2014
    Summary:Ag-Au and Ag-Pd alloy triangular hollow nanoframes were prepared using galvanic replacement (GR) reactions of Ag nanoprisms with HAuCl < inf > 4 < /inf > and Na < inf > 2 < /inf > PdCl < inf > 4 < /inf > in an aqueous solution. Their growth mechanisms were studied by observing transmission electron microscopic (TEM) and TEM-energy dispersed X-ray spectroscopic (EDS), XRD, and ultraviolet (UV)-visible (Vis)-near infrared (NIR) extinction spectral data. Results show that Ag-Au alloy triangular frames start with formation of a truncated prism, followed by expansion of a hollow structure to the interior of the prism, reformation of the triangular shape, and finally formation of a triangular frame at ambient temperature within a few minutes. On the other hand, triangular Ag-Pd alloy plates are slowly formed by the addition of Na < inf > 2 < /inf > PdCl < inf > 4 < /inf > and heating at 100 °C for 30-120 min. Results show that post-treatment using saturated NaCl solution is effective for the transformation of Ag-Pd alloy nanoplates to Ag-Pd nanoframes. The difference in the formation of nanoframes is explained by the difference in the dealloying rates between Ag-Au alloys by AuCl < inf > 4 < /inf > < sup > - < /sup > and Ag-Pd alloys by Pd < sup > 2+ < /sup > . XRD data suggested that hexagonally closed packed (hcp) layers are involved as major components of the triangular Ag-Au and Ag-Pd alloy nanoframes. © 2014 The Royal Society of Chemistry.
  • High-performance recycling system for waste plastics using raman identification, Hirofumi Kawazumi, Akihiro Tsuchida, Tomoya Yoshida, Yasuo Tsuchida, Progress in Sustainable Energy Technologies Vol II: Creating Sustainable Development, 519 - 529, Jan. 01 2014
    Summary:© Springer International Publishing Switzerland 2014. Raman spectroscopy has potential for application to waste plastic recycling when large-scale, accurate sorting processes are required. We developed a high-speed Raman identifier with a 3-ms measuring time. This identifier was successfully integrated with an on-line sorting system in a shredded plastic recycling plant. A practical-scale (200-600 kg/h) demonstration facility was constructed with 50 Raman apparatuses on a 30-cm-wide conveyor (speed: 100 m/min). This facility included preprocessing using specific gravity classification and putty removal. The Raman identification system was used to control air jets to sort polypropylene, polystyrene and acrylonitrile-butadiene-styrene copolymer with high accuracy from shredded plastics from post-consumer electrical appliances. Raman plastic identification can also provide solutions to problems at recycling sites such as the detection of brominated flame-retardants and the identification of black plastics.
  • Synthesis and growth mechanism of triangular Ag-rich AgAu alloy prisms in an aqueous solution in the presence of PVP, citrate and H2O 2, Masaharu Tsuji, Masaharu Tsuji, Masaharu Tsuji, Atsuhiko Yajima, Mika Hamasaki, Masashi Hattori, Masahito Mitarai, Hirofumi Kawazumi, CrystEngComm, 15, 7688 - 7695, Oct. 14 2013
    Summary:The effects of the addition of a small amount of HAuCl 4 · 4H 2 O in the preparation of triangular Ag prisms from an aqueous AgNO 3 -NaBH 4 -polyvinylpyrrolidone (PVP)-trisodium citrate (Na 3 CA)-H 2 O 2 solution were studied by monitoring time-dependent surface plasmon resonance (SPR) bands in the UV-vis region and by analyzing the data obtained from transmission electron microscopic (TEM) images and TEM-energy dispersed X-ray spectroscopy (EDS). The results show that Ag-rich AgAu alloy triangular prisms are formed by the addition of a small amount of AuCl 4 - ions. At first, small Au seeds were formed without latent time, along with spherical Ag-rich AgAu alloy particles. Then, a spherical-to-prism (STP) transformation of the AgAu alloy particles occurred. The plasmon band of the AgAu prism shifts slightly to red with the increasing concentration of HAuCl 4 ·4H 2 O. © 2013 The Royal Society of Chemistry.
  • Rapid transformation from spherical nanoparticles, nanorods, cubes, or bipyramids to triangular prisms of silver with PVP, citrate, and H 2O 2, Masaharu Tsuji, Masaharu Tsuji, Satoshi Gomi, Yoshinori Maeda, Mika Matsunaga, Sachie Hikino, Keiko Uto, Takeshi Tsuji, Hirofumi Kawazumi, Langmuir, 28, 8845 - 8861, Jun. 19 2012
    Summary:Rapid sphere-to-prism (STP) transformation of silver was studied in aqueous AgNO 3 /NaBH 4 /polyvinylpyrrolidone (PVP)/trisodium citrate (Na 3 CA)/H 2 O 2 solutions by monitoring time-dependent surface plasmon resonance (SPR) bands in the UV-vis region, by examining transmission electron microscopic (TEM) images, and by analyzing emitted gases during fast reaction. Roles of PVP, Na 3 CA, and H 2 O 2 were studied without addition of a reagent, with different timing of each reagent's addition, and with addition of H 2 O 2 to mixtures of spheres and prisms. Results show that prisms can be prepared without addition of PVP, although it is useful to synthesize smaller monodispersed prisms. A new important role of citrate found in this study, besides a known role as a protecting agent of {111} facets of plates, is an assistive agent for shape-selective oxidative etching of Ag nanoparticles by H 2 O 2 . The covering of Ag nanoparticles with carboxylate groups is necessary to initiate rapid STP transformation by premixing citrate before H 2 O 2 addition. Based on our data, rapid prism formation starts from the consumption of spherical Ag particles because of shape-selective oxidative etching by H 2 O 2 . Oxidative etching of spherical particles by H 2 O 2 is faster than that of prisms. Therefore, spherical particles are selectively etched and dissolved, leaving only seeds of prisms to grow into triangular prisms. When pentagonal Ag nanorods and a mixture of cubes and bipyramids were used as sources of prisms, rod-to-prism (RTP), cube-to-prism (CTP), and bipyramid-to-prism (BTP) transformations were observed in Ag nanocrystals/NaBH 4 /PVP/Na 3 CA/H 2 O 2 solutions. Shape-selective oxidative etching of rods was confirmed using flag-type Ag nanostructures consisting of a triangular plate and a side rod. These data provide useful information for the size-controlled synthesis of triangular Ag prisms, from various Ag nanostructures and using a chemical reduction method, having surface plasmon resonance (SPR) bands at a desired wavelength. © 2012 American Chemical Society.
  • Identification and Degradation Estimation of Waste Plastics for Recycling Using Raman Spectroscopy, Tomoya Yoshida, Yasuo Tsuchida, Akihiro Tsuchida, Hirofumi Kawazumi, Bunseki Kagaku, 61, 1027 - 1032, Jan. 01 2012
    Summary:Large-scale mechanical recycling of waste plastics requires useful sorting techniques. We have developed a high-speed, accurate identifier based on Raman spectroscopy for recycling PP, PS and ABS from post-consumer electrical appliances. It consists of a high-power diode laser (785 nm), a large numeric aperture optical system and a high-speed signal-processing on-board circuit. Small pieces (less than 10-mm square) of the plastics could be identified with a 3-ms measuring time on a conveyor belt (speed, 100 m min -1 ). The 50 Raman identifiers successfully work in parallel in a practical-scale demonstration facility, and a purity of more than 95 % is achieved from shredded plastics at a throughput of 200 - 600 kg h -1 . Multivariable analysis using the Mahalanobis distance could reveal a correlation between distortions of the Raman spectra and the weight losses in thermogravimetry to estimate the degradation of the waste plastics. © 2012, The Japan Society for Analytical Chemistry. All rights reserved.
  • Redispersion of dried gold nanorods in the presence of 6-amino-1- hexanethiol hydrochloride, Kanako Honda, Hirofumi Kawazumi, Naotoshi Nakashima, Yasuro Niidome, Journal of Nanoparticle Research, 13, 3413 - 3421, Aug. 01 2011
    Summary:Aggregates of phosphatidylcholine-passivated gold nanorods were prepared by the addition of hydrochloric acid in the presence of 6-amino-1-hexanethiol hydrochloride (AHT). The aggregates dried in vacuum formed a solid film showing a metallic gold color. In spite of the absence of the stable surface-wrapping agents, such as balky polymer or thiol-molecules that form stable self-organized films on a gold surface, the dried aggregates dispersed again in water. The redispersed gold nanorods in water did not form aggregates. If the dried nanorods were kept at room temperature for 24 h, they did not disperse in water again; however, at -30 °C, some of gold nanorods could be redispersed in water. At -80 °C, gold nanorods could be redispersed in water as colloidal nanoparticles even after 2 months. The phosphatidylcholine and AHT molecules on the nanorod surfaces contributed to the suppression of the contact of nanorods, which were in the metallic gold color films. © 2011 Springer Science+Business Media B.V.
  • Multidigestion in continuous flow tandem protease-immobilized microreactors for proteomic analysis, Hiroshi Yamaguchi, Masaya Miyazaki, Masaya Miyazaki, Hirofumi Kawazumi, Hideaki Maeda, Hideaki Maeda, Hideaki Maeda, Analytical Biochemistry, 407, 12 - 18, Dec. 01 2010
    Summary:Proteolysis by sequence-specific proteases is the key step for positive sequencing in proteomic studies integrated with mass spectrometry (MS). The conventional method of in-solution digestion of protein is a time-consuming procedure and has limited sensitivity. In this study, we report a simple and rapid system for the analysis of protein sequence and protein posttranslational modification by multienzymatic reaction in a continuous flow using the enzyme (trypsin, chymotrypsin, or alkaline phosphatase)-immobilized microreactor. The feasibility and performance of the single microreactor and tandem microreactors that were connected by the different microreactors were determined by the digestion of nonphosphoprotein (cytochrome c) and phosphoproteins (β-casein and pepsin A). The single microreactor showed rapid digestion compared with that of in-solution digestions. Multiple digestion by the tandem microreactors showed higher sequence coverage compared with that by in-solution or the single microreactor. Moreover, the tandem microreactor that was made by using the combination of protease-immobilized microreactor and phosphatase-immobilized microreactor showed the capability for phosphorylation site analysis in phosphoproteins without the use of any enrichment strategies or radioisotope labeling techniques. This approach provides a strategy that can be applied to various types of linking microreactor-based multienzymatic reaction systems for proteomic analysis. © 2010 Elsevier Inc.
  • Label-free biosensor using polyion-modified gold nanorods adsorbed on a glass substrate, Kanako Honda, Hirofumi Kawazumi, Naotoshi Nakashima, Yasuro Niidome, Chemistry Letters, 39, 992 - 993, Sep. 06 2010
    Summary:Gold nanorods (NRs), which were modified with polyions, were fixed on polycation-modified glass substrates. Adsorption of antibodies and antigens on the glass substrates induced large peak shifts (44 nm) of longitudinal surface plasmon bands in the near-infrared region. The shifts were assignable to changes of refractive indices of polyion layers at the glass surfaces. © 2010 The Chemical Society of Japan.
  • Rapid synthesis of Ag@Ni core-shell nanoparticles using a microwave-polyol method, Masaharu Tsuji, Masaharu Tsuji, Sachie Hikino, Mika Matsunaga, Yoshiyuki Sano, Tomoe Hashizume, Hirofumi Kawazumi, Materials Letters, 64, 1793 - 1797, Aug. 31 2010
    Summary:Mixtures of AgNO 3 and NiSO 4 ·6H 2 O, NiCl 2 ·6H 2 O, or Ni(NO 3 ) 2 ·6H 2 O were reduced in ethylene glycol (EG) in the presence of NaOH and poly(vinylpyrrolidone) (PVP) under microwave (MW) heating for 10 min. Then, we succeeded in the synthesis of Ag core-Ni shell nanoparticles, denoted as Ag@Ni, in high yield. The formation of Ag@Ni particles was confirmed using energy dispersed X-ray spectroscopic (EDS) measurements and selected area electron diffraction (SAED) patterns. The growth mechanism of Ag@Ni is discussed. The UV-Vis spectra of Ag@Ni were similar to those of Ni particles. © 2010 Elsevier B.V. All rights reserved.
  • Identification of shredded plastics in milliseconds using raman spectroscopy for recycling, Akihiro Tsuchida, Hirofumi Kawazumi, Arikata Kazuyoshi, Tuchida Yasuo, Proceedings of IEEE Sensors, 1473 - 1476, Dec. 01 2009
    Summary:Raman Spectroscopy is able to identify plastic components, similar to infrared absorption. This paper shows the potential application of Raman spectroscopy to post-consumer plastic recycling when massive and accurate sorting processes are required. We developed a high-speed Raman apparatus for scanning with an appropriate wavelength region of less as 1.5 milliseconds, and an analyzing methodology that uses a discrimination function. We successfully implemented this technique in a shredded plastic recycling plant. The online sensing system successfully carried out more than three hundred cycle decisions per second. ©2009 IEEE.
  • Plasmon-enhanced photocurrent generation from self-assembled monolayers of phthalocyanine by using gold nanoparticle films, Kosuke Sugawa, Tsuyoshi Akiyama, Tsuyoshi Akiyama, Hirofumi Kawazumi, Sunao Yamada, Sunao Yamada, Sunao Yamada, Langmuir, 25, 3887 - 3893, Mar. 17 2009
    Summary:The effect of localized electric fields on the photocurrent responses of phthalocyanine that was self-assembled on a gold nanoparticle film was investigated by comparing the conventional and the total internal reflection (TIR) experimental systems. In the case of photocurrent measurements, self-assembled monolayers (SAMs) of a thiol derivative of palladium phthalocyanine (PdPc) were prepared on the surface of gold-nanoparticle film that was fixed on the surface of indiu m-tin-oxide (ITO) substrate via a polyion (PdPc/AuP/polyion/ITO) or on the ITO surface (PdPc/ITO). Photocurrent action spectra from the two samples were compared by using the conventional spectrometer, and were found that PdPc/AuP/polyion/ITO gave considerably larger photocurrent signals than PdPc/ITO under the identical concentration of PdPc. In the case of the TIR experiments for the PdPc/AuP/polyion/ITO and the PdPc/AuP/Glass systems, incident-angle profiles of photocurrent and emission signals were correlated with each other, and they were different from that of the PdPc/ITO system. Accordingly, it was demonstrated that the photocurrent signals were certainly enhanced by the localized electric fields of the gold-nanoparticle film. © 2009 American Chemical Society.
  • Formation of gold nanorod-myoglobin aggregates by electrostatic interactions and their photochemical properties, Rumiko Kitagawa, Kanako Honda, Hirofumi Kawazumi, Yasuro Niidome, Naotoshi Nakashima, Sunao Yamada, Japanese Journal of Applied Physics, 47, 1374 - 1376, Feb. 15 2008
    Summary:A novel aggregate of gold nanorods (NRs) and myoglobin (Mb) was successfully fabricated by electrostatic interactions between the NR and Mb using positively charged biocompatible NRs. The aggregation induced some deformation of Mb, as was evaluated from circular dichroism measurements. Pulsed 1064nm laser irradiation to the aggregate has released some of the Mb proteins from the aggregate that resulted in the concomitant reshaping of the gold NRs in the aggregate. Some deformations of Mb were observed resulting from aggregation and subsequent laser irradiation. © 2008 The Japan Society of Applied Physics.
  • Surface modification of gold nanorods with synthetic cationic lipids, Yasuro Niidome, Kanako Honda, Keisuke Higashimoto, Hirofumi Kawazumi, Sunao Yamada, Naotoshi Nakashima, Yoshihiro Sasaki, Yoshihiko Ishida, Jun Ichi Kikuchi, Chemical Communications, 3777 - 3779, Sep. 19 2007
    Summary:Colloidal gold nanorods (GNRs), which were passivated with cationic cerasome-forming lipids having triethoxysilyl groups, were obtained in the aqueous phase by sonication of the mixture of lipids and GNRs. © The Royal Society of Chemistry.
  • Control of laser-induced deposition of gold nanoparticles on glass substrates for localized surface plasmon sensing, Kanako Honda, Yasuro Niidome, Hirofumi Kawazumi, Sunao Yamada, Bunseki Kagaku, 55, 675 - 679, Nov. 27 2006
    Summary:The irradiation of a pulsed laser (532 nm 10 Hz, 10 mJ/pulse) on dodecanethiol-passivated gold nanoparticles in cyclohexane resulted in the deposition of gold nanoparticles onto a glass substrate. The mode values and the spreads of the size distribution of the laser-deposited gold nanoparticles could be controlled with the initial size of colloidal gold nanoparticles and the laser irradiation time. The initial gold nanoparticles of 2 nm and the 1-minute laser irradiation resulted in large deposited gold nanoparticles (mode value, 16 nm; distribution spread, 9.1 nm). The larger initial gold nanoparticles (20 nm) and the longer laser irradiation (5 minutes) provided the fragmentized deposition of gold nanoparticles (mode value, 10 nm; distribution spread, 7.7 nm) which showed a linear correlation between the peak shifts of localized surface plasmon bands and the refractive indexes of the surrounding solvents. © 2006 The Japan Society for Analytical Chemistry.
  • End-to-end assemblies of gold nanorods adsorbed on a glass substrate modified with polyanion polymers, Kanako Honda, Yasuro Niidome, Naotoshi Nakashima, Hirofumi Kawazumi, Sunao Yamada, Chemistry Letters, 35, 854 - 855, Aug. 05 2006
    Summary:Phosphatidylcholine-passivated gold nanorods (NRs) adsorbed on polyanion-modified glass substrates. The NRs on glass substrates formed end-to-end assemblies showing red-shifted and broaden longitudinal surface plasmon (SP) bands. Addition of aminohexanethiol (AHT) induced dumping of SP bands but increased the density of NRs on glass surfaces. Thiol groups of AHT were effective to change the properties of NR assemblies on glass surfaces. Copyright © 2006 The Chemical Society of Japan.
  • Mechanism of reaction efficiency enhancement in microchannels studieied by spectroscopic visualization and numerical simulation, Hirofumi Kawazumi, Kenichi Kanno, Masayuki Fujii, Yoshiko Yamaguchi, Hideaki Maeda, Hideaki Maeda, Micro Total Analysis Systems - Proceedings of MicroTAS 2006 Conference: 10th International Conference on Miniaturized Systems for Chemistry and Life Sciences, 1336 - 1338, Jan. 01 2006
    Summary:The mechanism of high reaction efficiency of an organic condensation reaction and an enzyme hydrolysis in microreactors was studied by using the on-line visualization and numerical simulation for spatial distribution of the products. The characteristic fluidic behavior appeared to play an important role in the reaction efficiency enhancement. © 2006 Society for Chemistry and Micro-Nano Systems.
  • Rapid synthesis of gold nanostructures by a microwave-polyol method with the assistance of CnTAB (n=10, 12, 14, 16) or C16PC, Masaharu Tsuji, Masaharu Tsuji, Masaharu Tsuji, Kisei Matsumoto, Kisei Matsumoto, Takeshi Tsuji, Takeshi Tsuji, Takeshi Tsuji, Hirofumi Kawazumi, Materials Letters, 59, 3856 - 3860, Dec. 01 2005
    Summary:Gold nanostructures have been synthesized by a microwave(MW)-polyol method with the assistance of such cationic surfactants as alkyltrimethyl ammonium bromide (C n TAB: n = 10-16, even numbers) or cetylpryridinium chloride (C 16 PC). Although major products were spherical aggregates for C n TAB (n = 10, 12, 14), triangular, pentagonal, and hexagonal nanoplates were preferentially synthesized using C 16 TAB. Spherical spike-ball structures were prepared through C 16 PC. These results indicated that the morphology of gold nanostructures prepared by the MW-polyol method depends both on the chain length of hydrophobic alkyl group and on the hydrophilic head group. © 2005 Elsevier B.V. All rights reserved.
  • Compact surface plasmon resonance (SPR) immunosensor using multichannel for simultaneous detection of small molecule compounds, Hirofumi Kawazumi, K. Vengatajalabathy Gobi, Kazuya Ogino, Hideaki Maeda, Norio Miura, Sensors and Actuators, B: Chemical, 108, 791 - 796, Jul. 22 2005
    Summary:A compact, portable SPR immunosensor designed for on site analysis of low-molecular-weight compounds by immunosensing is developed in the dimensions of 16 cm × 9 cm × 6 cm with four sensing microchannels. Highly sensitive and selective analysis of benzo[a]pyrene and 2-hydroxybiphenyl is realized by using an indirect competitive immunoreaction based on surface plasmon resonance (SPR) detection. A multi-microchannel flow-cell module employed here provides referencing channels to compensate bulk refractive index changes and temperature variations. It has been successfully used for simultaneous detection of the two compounds and for improvement of baseline stability by using the reference channels. Sensitivity of the compact, portable SPR sensor to ppb levels of the two compounds was equivalent to that obtained with a conventional SPR apparatus. © 2004 Elsevier B.V. All rights reserved.
  • Acid-base equilibrium constants and distribution coefficients of aminopyrene between the surface and bulk of liquid water as studied by a laser two-photon ionization technique, Miki Sato, Akira Harata, Yoshihiko Hatano, Teiichiro Ogawa, Takeshi Kaieda, Takeshi Kaieda, Kohshin Ohmukai, Kohshin Ohmukai, Hirofumi Kawazumi, Hirofumi Kawazumi, Journal of Physical Chemistry B, 108, 12111 - 12115, Aug. 12 2004
    Summary:The pH-dependent amount of aminopyrene adsorbed at the water surface was measured using a laser two-photon ionization technique. The distribution coefficients of neutral and cationic aminopyrene between the surface and bulk of liquid water were determined to be 9.6 × 10 -6 m and 2.5 × 10 -7 m, respectively, The acid-base equilibrium constant, pK a , of aminopyrene on the water surface was determined to be 2.0, while that of the same molecule in bulk water was 3.6 × 0.1. These results show that neutral aminopyrene tends to stay on the water surface, resulting in equilibrium shifts toward the neutral form. It is demonstrated that laser two-photon ionization is a powerful method to analyze the equilibria of a small amount of molecules, 0.17pmol/cm 2 , adsorbed at the water surface.
  • Visualization of fluidic and reaction dynamics in microchannels, H. Kawazumi, A. Muraki, K. Kanno, H. Maeda, 2003 Nanotechnology Conference and Trade Show - Nanotech 2003, 1, 98 - 101, Dec. 01 2003
    Summary:An easy-to-use and low cost microreactor made of polymethylmethacrylate was mechanically fabricated with a microchannel (200 μm × 200 μm). The laminar flow behavior was visualized by using CCD camera images of red and green aqueous solutions. Numeric Data of red and green components in the images could reveal the fluidic behavior in the microchannel because the spatial spectroscopic information corresponds to the fluidic dynamics of the color solution. Effects of corner shapes in a turn, flow rate and surface roughness were observed on the mixing of the laminar flows. The progress of an enzyme reaction, hydrolysis with β-galactosidase, was also visualized by using the absorption of the product. Non-uniform distributions of the reaction occurrence led to an apparent enhancement of the reaction.
  • Development of SPR Immunosensing System Using MicroChannel Cell for Simultaneous Detection of Several Endocrine-Disrupting Chemicals, Norio Miura, K. Vengatajalabathy Gobi, Yukihiro Shoyama, Hideaki Maeda, Hirofumi Kawazumi, Hiroyuki Iwasaka, IEEJ Transactions on Sensors and Micromachines, 123, 217 - 223, Jan. 01 2003
    Summary:The endocrine-disrupting chemicals affect the functioning of hormones of animals and are called “environmental hormones”. They exist in various environments at very low concentrations in the range of ppt to ppb levels. Thus, highly sensitive determination of environmental hormones with high selectivity is indispensable in regulating the ecosystem, and the instrumentation that allows the on-site analysis of environmental hormones is paid much attention. In this research project, we are aiming at development of new optical immunosensing system for highly sensitive, selective, on-site and simultaneous detection of several environmental hormones at low cost. We report here the results of our research investigations on application of immunosensing technique to highly sensitive detection of environmental hormones, preparation of monoclonal antibodies, fabrication of the microchannel, miniaturization of the surface-plasmon-resonance detector, design of the compact total-sensing-system. © 2003, The Institute of Electrical Engineers of Japan. All rights reserved.
  • Enhanced enzymatic reactions in a microchannel reactor, Kenichi Kanno, Hirofumi Kawazumi, Masaya Miyazaki, Hideaki Maeda, Masayuki Fujii, Masayuki Fujii, Australian Journal of Chemistry, 55, 687 - 690, Dec. 01 2002
    Summary:Organic and enzymatic reactions in microchannel reactors were discussed. Hydrolytic activity of a microchannel pre-treated with enzyme solution was studied. It was found that the reaction rate in microchannel is much faster than the micro test tube. Mass transfer is also much more efficient in microchannel.
  • Observation of fluidic behavior in a polymethylmethacrylate-fabricated microchannel by a simple spectroscopic analysis, Hirofumi Kawazumi, Asuka Tashiro, Kazuya Ogino, Hideaki Maeda, Lab on a Chip, 2, 8 - 10, Feb. 01 2002
    Summary:An easy-to-use and low cost microreactor made of polymethylmethacrylate was mechanically fabricated with a microchannel (200 μm × 200 μm). The laminar flow behavior was investigated by visualizing the flow of red and green aqueous solutions. Digitized color images from a CCD camera were analyzed by resolving the color in RGB mode. Numeric data from red and green color components in the images could reveal the fluidic behavior in the microchannel because the spatial spectroscopic information corresponds to the color solution flows. Effects of corner shapes in a turn, flow rate and surface roughness were observed on the mixing of the laminar flows. A right angle turn and unevenness of ±10% of the inner wall surface almost mixed the two color laminar flows.
  • Water-content analysis by photothermal spectrometry with a near-infrared diode laser, Hirofumi Kawazumi, Takanobu Ukawa, Tomohiro Watanabe, Bunseki Kagaku, 50, 911 - 914, Dec. 01 2001
    Summary:Photothermal spectrometry for water is described in which high-power diode laser with a wavelength coincident with strong vibrational overtone absorption in a near-infrared region was used. In the thermal lens technique, an apparatus consisting of only solid-state devices, such as optical fibers, a fiber-coupler and photodiode, was used. The optical fibers acted as not only optical paths, but also as collimation devices. A water content of 0.15% in acetonitrile could be detected, and a linear analytical curve was obtained in the range of 0%∼ 7% with a 1478 nm, 100 mW diode laser at an intensity modulation frequency of 20 Hz. A photoacoustic technique could be also applied to water in acetonitrile and water adsorbed on molecular sieves by using a cell equipped with a cylindrical piezoelectric ceramic. These techniques can be a versatile water-analysis tool for the process monitoring and control. © 2001 The Japan Society for Analytical Chemistry.
  • Acid-base equilibrium constants at the water surface and distribution coefficients between the surface and the bulk as studied by the laser two-photon ionization technique, Miki Sato, Takeshi Kaieda, Kohshin Ohmukai, Hirofumi Kawazumi, Akira Harata, Teiichiro Ogawa, Journal of Physical Chemistry B, 104, 9873 - 9877, Oct. 26 2000
    Summary:A new method has been proposed to determine the equilibrium between the bulk and the surface by directly measuring surface concentrations using laser two-photon ionization. This method has been applied to pyrenebutyric acid. The surface concentrations depended on the pH of the solution and were analyzed on the basis of two equilibrium constants and two distribution coefficients. Most pyrenebutyric acid stays on the surface at pH = 2.2. The equilibrium constant, pK a , of pyrenebutyric acid on the water surface was determined to be 7.85 ± 0.1 3 , and this value is shifted to higher value than that in the bulk (4.76). The distribution coefficient of the neutral pyrenebutyric acid was determined as (5.9 ± 2.8) × 10 -2 m, and that of pyrenebutyric anion as (4.82 ± 0.1) × 10 -5 m. The ratio of the distribution coefficient of the neutral pyrenebutyric acid to that of pyrenebutyric anion was determined to be (1.2 ± 0.6) × 10 3 . These findings indicate that the equilibrium shifts toward the neutral form on the water surface. Laser two-photon ionization was found to be a sensitive and powerful technique to analyze equilibrium on the surface and that between the surface and the bulk. © 2000 American Chemical Society.
  • Determination of two photon absorption cross section of fluorescein using a mode locked titanium sapphire laser, Joon Myong Song, Joon Myong Song, Takanori Inoue, Takanori Inoue, Hirofumi Kawazumi, Teiichiro Ogawa, Teiichiro Ogawa, Analytical Sciences, 15, 601 - 603, Jun. 01 1999
  • Single Molecule Detection by Laser Two-Photon Excited Fluorescence in a Capillary Flowing Cell, Joon Myong Song, Joon Myong Song, Takanori Inoue, Takanori Inoue, Hirofumi Kawazumi, Teiichiro Ogawa, Teiichiro Ogawa, Analytical Sciences, 14, 913 - 916, Dec. 01 1998
    Summary:The two-photon excited fluorescence of fluorescein and Rhodamine B in a flowing sample cell was observed using a self mode-locked Ti-sapphire laser (180 fs pulse). The detection limit of fluorescein was less than 2 molecules in the probe volume. The single molecule detection of Rhodamine was successfully performed in a flowing cell, and the number of photon bursts agreed approximately with that expected.
  • Development of an interfacial thermal lens technique: Monitoring the dissolving process of amphiphilic molecules at the hexane-water interface, Hirofumi Kawazumi, Takeshi Kaieda, Takanori Inoue, Teiichiro Ogawa, Chemical Physics Letters, 282, 159 - 163, Jan. 09 1998
    Summary:An interfacial thermal lens technique has been developed for monitoring amounts of molecules at a liquid-liquid interface. A thin thermal lens can be observed for amphiphilic molecules, 10-(1-pyrene)decanoic acid and 4-(1-pyrene)butanoic acid, expanded at a hexane-phosphate buffer solution interface. The thermal lens spectrophotometry offers a linear response to amounts of the expanded molecule and its minimum detectable amount is 1.0×10 -10 mol corresponding about 1/100-monolayer. The signal decay depended on the pH of aqueous phase and the faster decay at lower pH was ascribed to the dissolving process of the molecules from the interface into hexane.
  • Surface Density of Pyrenesulfonic Acid at the Air-Water Interface as Determined by Laser Two-Photon Ionization: Effect of pH and Salt, Miki Sato, Teiichiro Ogawa, Takeshi Kaieda, Kohshin Ohmukai, Hirofumi Kawazumi, Analytical Sciences, 14, 855 - 856, Jan. 01 1998
  • Monitoring of dissolving processes of amphipathic molecules from aqueous surface by laser-induced two-photon ionization, Hirofumi Kawazumi, Takeshi Kaieda, Kohshin Ohmukai, Miki Sato, Takanori Inoue, Teiichiro Ogawa, Analytical Sciences, 13, 49 - 52, Dec. 01 1997
    Summary:Laser two-photon ionization technique has been applied to monitor dissolving processes of probe molecules from solution surfaces. The time courses of the photoionization charge decay were measured by changing the properties of the bulk phase after the addition of the amphipathic molecules. The dissolving rate of pyrenebutyric acid, aminopyrene and pyrenesulfonic acid was strongly depended on pH in the bulk solution. The dissociation equilibrium of the conjugated acid-base system governed the solubility of the amphipathic molecules. Effects of surfactants were also observed in the dissolving process of pyrenedecanoic acid.
  • Highly sensitive detection using laser two-photon excited fluorescence in capillary electrophoresis, Joon Myong Song, Takanori Inoue, Hirofumi Kawazumi, Teiichiro Ogawa, Journal of Chromatography A, 765, 315 - 319, Mar. 28 1997
    Summary:The laser two-photon excited fluorescence (LTPF) has been applied to a capillary electrophoresis (CE) system using a self mode-locked titanium-sapphire laser. The analytes were coumarine 440 (7-amino-4-methyl coumarine) and DCCS (7-diethyl aminocoumarine-3-carboxylic acid succinimidyl eater). The two-photon excited fluorescence emission spectrum of DCCS was identical to the one-photon excited fluorescence emission spectrum. The LTPF quantum efficiency increased through the addition of methanol to the buffer solution, and, as a result, the detection limit decreased. The detection limit of coumarine 440 was 8.0 amol, this value was as low as that obtained by one-photon excited fluorescence.
  • Application of an avalanche photodiode in a near-Geiger operation as a fluorescence detector for capillary electrophoresis, Hirofumi Kawazumi, Joon Myong Song, Takanori Inoue, Teiichiro Ogawa, Journal of Chromatography A, 744, 31 - 36, Sep. 13 1996
    Summary:A laser-induced fluorescence detection system for capillary electrophoresis has been developed by use of a semiconductor laser (655 nm) as an excitation light source and an avalanche photodiode (APD) as a fluorescence detector. The APD may be used in a near-Geiger condition by adjusting its bias voltage, and its internal gain to photoelectrons increases substantially. Subnanosecond time-resolved photon counting using the APD in the near-Geiger operation has provided very high sensitivity due to its well-defined photoelectron pulse shape and an enhancement of the counting efficiency. The detection limit of Oxazine 725 was 47 amol, which was about 100 times better than that using a photomultiplier.
  • Time-resolved photon-counting fluorimetry with a semiconductor laser for capillary electrophoresis, Joon Myong Song, Hirofumi Kawazumi, Takanori Inoue, Teiichiro Ogawa, Journal of Chromatography A, 727, 330 - 333, Mar. 15 1996
    Summary:Effects of the gate width and the gate delay on the signal-to-noise ratio were investigated for a laser-induced fluorescence detector of capillary electrophoresis using a pulsed semiconductor laser, a photomultiplier and a time-resolved photon counting method. Separation of fluorescence and background was easier for a fluoropher with a long lifetime.
  • Laser Fluorometry Using a Visible Semiconductor Laser and an Avalanche Photodiode for Capillary Electrophoresis, Joon Myong Song, Takanori Inoue, Teiichiro Ogawa, Hirofumi Kawazumi, Analytical Sciences, 11, 587 - 590, Jan. 01 1995
    Summary:A laser-induced fluorescence detection system for capillary electrophoresis using a visible semiconductor laser and an avalanche photodiode has been developed. These solid-state devices offer both reliability and compactness for instrumental design. A time-resolved photon-counting method with a subnanosecond resolution has reduced the large dark counts of the avalanche photodiode and the contribution from scattered light. The baseline fluctuation of the electropherogram is due to the shot noise of the avalanche photodiode. The detection limit (S/N=2) for a model dye compound, Oxazine 725, is 2.1 fmol as an injection amount. This value is comparable to that of the conventional laser fluorometry system with a gas laser and a photomultiplier. © 1995, The Japan Society for Analytical Chemistry. All rights reserved.
  • Time-delayed two-color two-photon ionization of anthracene, benzo [a] pyrene and pyrene in cyclohexane, Keiji Nakashima, Manabu Kise, Teiichiro Ogawa, Hirofumi Kawazumi, Sunao Yamada, Chemical Physics Letters, 231, 81 - 85, Dec. 16 1994
    Summary:Intermediate states of the two-photon ionization of the three aromatic molecules in cyclohexane were investigated using a time-delayed two-color technique. The S 1 state is a major intermediate for the two-photon ionization of anthracene and benzo [a] pyrene, while both the S 1 and S 2 states are intermediates for pyrene. Ionization through the short-lived S 2 state was enhanced through autoionization resonance. © 1994.
  • Two-photon ionization cross sections for the free ion production of naphthacene and fluoranthene in hexane, Hirofumi Kawazumi, Hirofumi Kawazumi, Yuji Isoda, Yuji Isoda, Teiichiro Ogawa, Journal of Physical Chemistry, 98, 170 - 173, Dec. 01 1994
    Summary:Naphthacene and fluoranthene in hexane showed photoconductivity signals upon excitation by 458-nm irradiation (200 mW) with a continuous-wave argon ion laser. The signals were quadratically proportional to the laser power and linearly proportional to the solute concentration, indicating a two-photon excitation-ionization. By evaluation of the signal intensity and laser beam parameters, two-photon ionization cross sections for the production of the free ions separating from geminate ion-electron pairs have been determined absolutely to be 2.2 × 10 -52 and 2.5 × 10 -54 cm 4 s/(molecule photon) for naphthacene and fluoranthene, respectively, at an electric field of 5000 V/cm. The former cross section of the ionization via a real state was about 100 times larger than the latter via a virtual state. The calculated quantum yield of naphthacene from the two-photon ionization cross section is smaller by about 6 orders of magnitude than the reported value of anthracene obtained by the pulsed laser excitation. © 1994 American Chemical Society.
  • Electron energy-loss spectra of toluene and xylenes, Etsuji Yamamoto, Toshifumi Yoshidome, Teiichiro Ogawa, Hirofumi Kawazumi, Journal of Electron Spectroscopy and Related Phenomena, 63, 341 - 346, Nov. 12 1993
    Summary:The electron energy-loss spectra of toluene, o-xylene, m-xylene and p-xylene have been measured at electron energies of 50 eV and of 3 eV above the threshold; the scattering angles were 23, 45 and 68° at 3 eV. The spectra of the four molecules are similar. Three new bands have been observed at 3.7-3.8, 4.6 and 5.5 eV, and they are assigned as transitions from the ground state to the first three triplet states. © 1993.
  • Diode laser-based indirect absorbance detector for capillary electrophoresis, Stephen J. Williams, Edmund T. Bergström, David M. Goodall, Hirofumi Kawazumi, Kenneth P. Evans, Journal of Chromatography A, 636, 39 - 45, Apr. 23 1993
    Summary:A near-infrared detector has been developed for use in capillary electrophoresis (CE). The detector has a double beam arrangement with signal- to-reference ratioing and operates with a 670-nm diode laser as the light source. The laser beam can be modulated to allow a.c. signal recovery using lock-in amplification. Near-infrared laser dyes have been investigated as background absorbers, and the singly-charged cationic dye rhodamine 700 found to exhibit suitable characteristics for use in indirect absorbance detection in methanol-water mixtures. Separations of a series of tetraalkylammonium compounds have been performed on both a commercial CE apparatus with indirect UV detection and on a home-made instrument incorporating the diode laser detector. The limit of detection (2 × peak-to-peak noise) for the tetrabutylammonium ion with diode laser-based indirect absorbance is 2 · 10 -5 M. Both positive and negative peaks are found for these positively- charged analytes displacing a positively charged background absorber. Transfer ratios for all peaks are quantitated and the results compared with theoretical treatments of displacement in indirect detection. For analytes with mobility less than the indirect absorbing ion, measurement of peak area leads directly to the quantity of analyte present in the sample solution. © 1993.
  • Two-photon ionization detection of adsorbed molecules on a metal surface at atmosphere pressure by 355-nm laser irradiation, H. Kawazumi, T. Yasuda, T. Ogawa, Analytica Chimica Acta, 283, 111 - 114, Jan. 01 1993
    Summary:Two-photon ionization was applied to the sensitive detection of aromatic molecules and dyes on a metal surface in ambient air by using the third harmonic of an Nd:YAG laser. The better quality of the Nd:YAG laser beam compared with a nitrogen laser improved the sensitivity. The detection limits were of the order of 10 -3 monolayer coverage. The dependence of the ionization signal on the molar absorptivity and the metal substrate was measured.
  • Application of Laser Multi-Photon Ionization Detection to Thin-Layer Chromatographic Plates, Hirofumi Kawazumi, To Oru Yasuda, Teiichiro Ogawa, Analytical Sciences, 9, 309 - 310, Jan. 01 1993
  • Differential indirect fluorescence detection for the reversed-phase microcolumn high-performance liquid chromatography, Hideki Nishimura, Tehchiro Ogawa, Hirofumi Kawazumi, Journal of Liquid Chromatography, 15, 2233 - 2245, Sep. 01 1992
    Summary:Differential indirect fluorescence detection was applied for reversed-phase microcolumn high-performance liquid chromatography of aliphatic alcohols. The differential measurement with single capillary cell and double beams improved dynamic reserve and detectability. The indirect detection system suitable for a visible semiconductor laser was developed with a deep-red dye, 3, 3,-dimethyk-xatricart-ocyanlne chloride. A mass detection limit was in the $ub-ng (nmol) range. © 1992, Taylor & Francis Group, LLC. All rights reserved.
  • Molecular Orientation of an Organized 2-(N-Octadecylamino)-naphthalene-6-sulfonic Acid Multilayer Determined by the Second-Harmonic Generation Technique, Toshiaki Koga, Teiichiro Ogawa, Hirofumi Kawazumi, Toshihiko Nagamura, Analytical Sciences, 8, 259 - 260, Jan. 01 1992
  • Trace Determination of Benzene and Aromatic Molecules in Hexane by Laser Two-Photon Ionization, Teiichiro Ogawa, Manabu Kise, To Oru Yasuda, Hirofumi Kawazumi, Sunao Yamada, Analytical Chemistry, 64, 1217 - 1220, Jan. 01 1992
    Summary:LaMr two-photon ionization of several aromatic molecules In hexane has been carried out with the fourth harmonics (266 nm) of a Nd-YAG laser as an excitation source. The photolonlzatlon current Is quadratlcally proportional to the laser pulse energy, Indicating two-photon Ionization. There Is a large blank signal due to the solvent (hexane) Ionization, and it has been canceled with a differential technique. The effect of laser pulse energy fluctuation has been corrected by an on-line normalization procedure. The photolonlzatlon current also depends on the molar absorptivity of the molecule, and the first step to Ionization should be excitation at 266 nm above the ground state. The detection limit ranges from 3.8 ppb for benzene to 61 ppt for pyrene. Analytical curves were linear for at least 3 orders of magnitude above the detection limits. © 1992, American Chemical Society. All rights reserved.
  • Laser Two-Photon Ionization of 4, 4″′-Bis[(2-butyloctyl)oxy]-p-quaterphenyl on a Platinum Surface in Ambient Air: Highly Sensitive Detection of Surface Molecules, Teiichiro Ogawa, To Oru Yasuda, Hirofumi Kawazumi, Analytical Sciences, 8, 81 - 82, Jan. 01 1992
  • Laser Two-Photon Ionization Detection of Aromatic Molecules on a Metal Surface in Ambient Air, Teiichiro Ogawa, To Oru Yasuda, Hirofumi Kawazumi, Analytical Chemistry, 64, 2615 - 2617, Jan. 01 1992
    Summary:A laser two-photon process can ionize a photoabsorbing molecule selectively though a one-photon resonant process without ionizing the bulk surface. By measuring the ionized species through photoconductivity, this technique has been found to be successful for highly sensitive detection of aromatic molecules on a metal surface in ambient air. The photocurrent was due to electron drift and oxygen anion drift in ambient air. The photocurrent signal of various aromatic molecules was approximately proportional to the absorbance at the laser wavelength. The detection limits were on the order of 10 -13 mol/cm 2 in favorable cases, which correspond to less than 1 % coverage of the surface. © 1992, American Chemical Society. All rights reserved.
  • Electron-impact dissociation of water as studied by the angular difference doppler profiles of the excited hydrogen atom, Teiichiro Ogawa, Nobuaki Yonekura, Masuo Tsukada, Masuo Tsukada, Satoru Ihara, Satoru Ihara, To O. Yasuda, Hideaki Tomura, Hideaki Tomura, Keiji Nakashima, Hirofumi Kawazumi, Journal of Physical Chemistry, 95, 2788 - 2792, Dec. 01 1991
    Summary:Dissociative excitation of water was investigated by measuring the Doppler profiles of the Balmer α and β lines of the excited hydrogen atom produced in e-H 2 O collisions, using a Fabry-Perot interferometer. The profiles were obtained at 55°, 90°, and 125° with respect to the electron beam. The translational energy distributions (TED) and the angular difference Doppler profiles were calculated through analyses of the profiles; results of H*(n=3) and H*(n=4) agree qualitatively. There are four major dissociation processes for the formation of the excited hydrogen atom. The first component is slow (TED mainly at 0-2 eV), and its formation is isotropic; this component is produced through initial excitation to Rydberg states converging to the B 2 B 2 (1b 2 ) -1 state and predissociation. The second component is fast (TED mainly at 3-7 eV), and its formation is anisotropic and parallel with respect to the electron beam. Thus, the symmetry of the initially excited Rydberg states is concluded to be B 2 ; this component is produced through direct dissociation of the Rydberg states converging to the 2 B 1 state. The third component is fast (TED mainly at 2-6 eV), and the direction of its formation is slightly perpendicular. Thus, the symmetry of the initially excited Rydberg states is concluded to be A 1 ; this component is produced through direct dissociation of the Rydberg states converging to the 2 A 1 (2a 1 ) -1 state. © 1991 American Chemical Society.
  • Magneto-optical rotation detector based on semiconductor laser for high-performance liquid chromatography, Hirofumi Kawazumi, Hideki Nishimura, Yukiaki Otsubo, Teiichiro Ogawa, Analytical Sciences, 7, 1479 - 1480, Jan. 01 1991
    Summary:A universal on-line detector based on a magneto-optical rotation (MOR) has been developed for high-performance liquid chromatography. A near-infrared semiconductor laser with a stable light intensity improves a chromatographic background. Detectability is in the μ-g range and linearity of an analytical curve is more than two orders of magnitude. © 1991, The Japan Society for Analytical Chemistry. All rights reserved.
  • Universal on-line detector for high-performance liquid chromatography via magneto-optical rotation, Hirofumi Kawazumi, Hideki Nishimura, Yukiaki Otsubo, Teiichiro Ogawa, Talanta, 38, 965 - 969, Jan. 01 1991
    Summary:Detecting changes in magneto-optical rotation is useful as a universal on-line detector for high-performance liquid chromatography. Such apparatus is similar to a polarimeter except for the external magnetic field on a flow cell. Two modulation modes suitable for the magneto-optical rotation detector are discussed. Use of a semiconductor laser provides better sensitivity than a He-Ne laser. The detection limit is 0.006% (w/w) for polyethylene glycol 20000 in a 20-μl injection. © 1991.
  • Universal Flow Detector Based on Magneto-Optical Rotation, Hirofumi Kawazumi, Hideki Nishimura, Teiichiro Ogawa, Analytical Sciences, 6, 135 - 136, Jan. 01 1990
  • Distributions over the 4s, 4p and 4d Sublevels and Their Emission Cross Sections of the Excited Hydrogen Atom Produced in e-CH4 and H2O Collisions, Keiji Nakashima, Teiichiro Ogawa, Masaharu Taniguchi, Masaharu Taniguchi, Hirofumi Kawazumi, Journal of the Physical Society of Japan, 59, 893 - 897, Jan. 01 1990
    Summary:Dissociation of CH4 and H2O induced in collisions with electrons was investigated by measuring decay curves of the intensity of the Balmer emission of the excited hydrogen atom H*(n=4). The azimuthal quantum number (s,p,d) distributions of H*(n=4) were obtained by a time-resolved single-photon counting method. The distribution (%) for methane is H*(4s):H*(4p):H*(4d)=42±4:4± 11:51 ±11 at the electron energy of 25-300 eV, and that for water is H*(4s):H*(4p):H*(4d)=27±5:15±11:55±11 at 23-300 eV. The emission cross sections of each sublevel were obtained at 35, 50, 100 and 300 eV. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.
  • Electron energy-loss spectra of methanol and assignments of its triplet states, Toshifumi Yoshidome, Hirofumi Kawazumi, Teiichiro Ogawa, Journal of Electron Spectroscopy and Related Phenomena, 53, 185 - 192, Jan. 01 1990
    Summary:The electron energy-loss spectra of methanol were measured at electron energies of 50, 20 and 2 eV above the threshold and at scattering angles of 0°-90°. Five new bands were found and assigned on the basis of intensity dependence on the incident electron energy and the scattering angle. A broad band at 6.3 eV was assigned as the 2a″-3s( 3 A″) transition and a band at 7.5 eV was assigned as the 2a″-3pa′ ( 3 A″) transition. Weak bands at 8.2 and 9.0 eV were assigned as the 2a″-3pa″ ( 3 A′) and the 2a″-3d( 3 A) transitions, respectively. A sharp band at 9.35 eV seemed to be a pseudo symmetry-forbidden transition. © 1990.
  • Distributions over the 4s, 4p and 4d sublevels and hydrogen atom emission cross sections following e-H2 collisions, Teiichiro Ogawa, Masaharu Taniguchi, Keiji Nakashima, Hirofumi Kawazumi, Chemical Physics, 137, 323 - 330, Oct. 15 1989
    Summary:The azimuthal quantum number (s, p, d) distributions of the excited hydrogen atom (n = 4) produced in electron-impact dissociation of H 2 were measured by a time-resolved single-photon counting method. Relative emission intensities at 19-32 eV were approximately I(4s): I(4p): I(4d) = 31:14:53, and those at 50-100 eV were 21:15:62; the cascade effect was small. The absolute emission cross sections (in units of 10 -20 cm 2 ) of three sublevels (s, p, d) were calculated: σ(4s) = 3.8, σ(4p) = 2.7 and σ(4d) = 12.3 at 100 eV. This distribution is consistent with a model in which the dissociation proceeds axially in the Σ and Π symmetries and the azimuthal quantum number distribution within each symmetry is statistical. © 1989.
  • Laser-based photoacoustic densitometer for two-dimensional scanning of thin-layer chromatographic plates, Hirofumi Kawazumi, Edwards S. Yeung, Applied Spectroscopy, 43, 249 - 253, Feb. 01 1989
    Summary:Laser-based photoacoustic densitometry was applied to two-dimensional analysis in thin-layer chromatography. An acousto-optic device was used to provide both intensity modulation and a rastering scan. The spatial resolution is 25×60 spots for an area of 25×50 mm on the thin-layer chromatographic plate. Three detection modes, normal modulation, resonant modulation, and unmodulated rapid scan modes were compared. Detection limits in the most sensitive mode and in the fastest mode are 350 pg with scan time of 153 s and 6.9 ng with scan time of 1.5 s, respectively.
  • Dissociation of HD: Dependence of Isotope Effects on the Principal Quantum Number, Keiji Nakashima, Hirofumi Kawazumi, Teiichiro Ogawa, Journal of the Physical Society of Japan, 58, 3857 - 3858, Jan. 01 1989
  • Resonant cell laser-based photoacoustic densitometer for thin-layer chromatography, Hirofumi Kawazumi, Edward S. Yeung, Applied Spectroscopy, 42, 1228 - 1231, Sep. 01 1988
    Summary:Photoacoustic spectroscopy was applied to the in situ densitometry of thin-layer chromatographic plates. Fast laser-scanning detection with signal enhancement was demonstrated at a resonant frequency of the cell. The use of phase difference between signal and background provided higher signal-to-noise ratios. Detection limit for Orange G was 170 pg, and the analytical curve was linear over three orders of magnitude.
  • Resonance enhanced two-photon ionization spectrometry of aromatic molecules in ambient pressure nitrogen gas, Sunao Yamada, Naoshi Adach, Hirofumi Kawazumi, Teiichiro Ogawa, BUNSEKI KAGAKU, 37, 216 - 220, Jan. 01 1988
    Summary:Various aromatic molecules have been detected simply and conveniently by measuring the photocurrent signal induced by resonance enhanced two-photon ionization. Volatile benzene derivatives were measured in the ppb~sub range by mixing the vapor of the analyte from a diffusion tube with nitrogen gas. Calibration curves were straight in the ppb~sub ppm range. Detection limits (S/N= 3) of eight benzene, derivatives were as low as ppb levels; the lowest detection limit was 0.8 ppb for aniline. The molecules with large molar absorptivities in isooctane gave the lower detection limits. Less volatile aromatic molecules were measured by the thermal vaporization technique; the solid sample was heated at a constant heating rate and the photocurrent signal was measured as a function of the temperature. Calibration curves were straight, and the lowest detection limit was 90 pg for triphenyl-amine. Some selective detections of mixtutes were possible within 10 min. This method may be useful for rapid identification and quantitation of organic adsorbates without any pretreatment. © 1988, The Japan Society for Analytical Chemistry. All rights reserved.
  • Laser photoionization detector for reversed-phase high performance liquid chromatography, Teiichiro Ogawa, Takashi Matsumoto, Hirofumi Kawazumi, Toshihiko Nagamura, Analytical Sciences, 4, 473 - 476, Jan. 01 1988
    Summary:The laser Iwo-photon ionization technique was applied to reversed-phase high performance liquid chromatography by using a free-falling jet detector (20 nl). Methanol, acetonitrile and a mixture of acetonitrile-water (90:10) were used in the mobile phase. The dependences of the detection limit on such experimental parameters as the electrode spacing and applied voltage were measured. The best detection limit was obtained at 0.5 mm spacing and at 60 V for acetonitrile. Although these solvents showed similar leakage currents, acetonitrile gave the best detection limit. The detection limit was 60 pg for pyrene, comparable with or better than that obtained by a UV absorption detector. © 1988, The Japan Society for Analytical Chemistry. All rights reserved.
  • Laser Photoionization Technique for Conventional, Semi-Microcolumn and Microcolumn High Performance Liquid Chromatography, Hirofumi Kawazumi, Takashi Matsumoto, Nariaki Sato, Sunao Yamada, Teiichiro Ogawa, Analytical Sciences, 4, 191 - 194, Jan. 01 1988
    Summary:Laser two-photon ionization detection for high performance liquid chromatography was investigated. A free-falling jet cell (20 nl) was used for a conventional system, and detection limit was 0.5 pg for pyrene. A droplet cell (80 nl) was used for a semi-micro and microcolumn systems; detection limits for pyrene were 8.4 and 1.6 pg, respectively. In both cases the detection limit was better than that for a UV absorption detector. The sensitivity and selectivity of this detector are shown with a three-dimensional chromatogram, in which retention times and excitation laser wavelengths are displayed. © 1988, The Japan Society for Analytical Chemistry. All rights reserved.
  • Translational energy distribution and asymmetry parameter of the excited hydrogen atom produced in e-C2H2 collisions: Dissociation dynamics of acetylene, Teiichiro Ogawa, Hideaki Tomura, Hideaki Tomura, Keiji Nakashima, Hirofumi Kawazumi, The Journal of Chemical Physics, 88, 4263 - 4267, Dec. 01 1987
    Summary:Dissociative excitation of acetylene induced in e-C 2 H 2 collisions was investigated by measuring the Doppler profile and its angular dependence from H*(n=4) at a resolution of 0.0065 nm. The translational energy distribution and the angular difference Doppler profile were calculated. The Balmer line was unpolarized. There are three major dissociation processes for H*(n=4) from C 2 H 2 ; their threshold energies and translational energy distributions are (1) 20.8, 0-2 eV, (2) ∼30, 3-5 eV, and (3) 35-40, 6-8 eV, respectively. Component 1 showed a clear anisotropy: the asymmetry parameter b is 0.5±0.1 and the anisotropy of atomic emission J p is 0. Thus, component 1 should be produced by predissociation through Rydberg states converging to the (2σ u ) -1 state. The decrease of b from the theoretical maximum is due to arbitrary direction of the momentum transfer vector and a relatively long lifetime of the intermediate excited states. Components 2 and 3 are also anisotropic and b > 0. © 1988 American Institute of Physics.
  • Laser Two-Photon Ionization Spectrometry of Perylene and Naphthacene in Hexane, Sunao Yamada, Nariaki Sato, Hirofumi Kawazumi, Teiichiro Ogawa, Analytical Chemistry, 59, 2719 - 2721, Nov. 01 1987
    Summary:The two-photon Ionization spectra of perylene and naphthacene in hexane have been measured with tunable dye lasers. They have shown structure, which can be correlated with the one-photon absorption spectra. The signal-to-nolse (S/N) ratio has been evaluated as functions of the excitation wavelength and the laser pulse energy, and the detection limit depended on the excitation wavelength, the laser pulse energy, and the molar absorptivity. The lowest detection limits (S/N = 3) of peryiene and naphthacene were 50 pg/mL at 383 nm and 20 pg/mL at 407 nm, respectively; these dye laser results were superior to those obtained by nitrogen-laser excitation. © 1987, American Chemical Society. All rights reserved.
  • Dissociation of water by controlled electron impact: rotational and translational energies of OH(X 2Πi) fragment, Hirofumi Kawazumi, Teiichiro Ogawa, Chemical Physics, 114, 149 - 155, May 15 1987
    Summary:Formation of OH(X 2 Π i ) by controlled electron impact on H 2 O has been studied by laser-induced fluorescence technique and its rotational and translational energies have been determined from the peak intensity and the Doppler profile. The rotational distribution of OH was Boltzmann-type with a characteristic temperature T rot = 470 ± 50 K for the P 1 lines at 100 eV. The translational energy distribution of OH was composed of three components with most probable values of ≈ 0, 0.09 and 0.22 eV. These three components have been assigned to three major excitation-dissociation processes of H 2 O: dissociation through H 2 O(A 1 B 1 ), H 2 O + (B 2 B 2 ) and H 2 O + ( 2 B 1 ), and Rydberg states converging to the two ionized states. © 1987.
  • Angular difference Doppler profiles of the excited hydrogen atom produced in eCH4 collisions and dissociation dynamics of methane, Teiichiro Ogawa, Hideaki Tomura, Keiji Nakashima, Hirofumi Kawazumi, Chemical Physics, 113, 65 - 72, Apr. 01 1987
    Summary:The Doppler profiles of the Balmer-β lines of H * (n = 4) produced in eCH 4 collisions were measured at a resolution of 0.0065 nm. The angular difference Doppler profiles, the difference of two profiles taken at 90° and 45° (55°) with respect to the electron beam, were calculated. Component 1 (the peak of the translational energy distribution at 3 eV and the threshold energy at 21.6 eV) showed a clear anisotropy; the asymmetry parameter b is 0.24 and the anisotropy of atomic emission J p is 0. The asymmetry parameter shows that the dissociation is slow with respect to the rotation, and/or that the dissociation proceeds toward different directions with respect to the transition dipole moment. These finding that non-spherical Rydberg states converging to either the A 2 A 1 state or the (1t -2 2 state of CH + 4 are intermediate states for the formation of component 1. © 1987.
  • Absolute cross sections for the formation of CN(X, v = 0) produced by controlled electron impact on BrCN and CH3CN, Hirofumi Kawazumi, Teiichiro Ogawa, Chemical Physics Letters, 140, 458 - 461, Jan. 01 1987
    Summary:The absolute cross section for the electron-impact formation of a radical fragment is determined by measuring its laser-induced fluorescence in comparison with that of N 2 + (X, v = 0); cross sections for CN(X, v = 0) from BrCN and CH 3 CN are 5.5 × 10 -17 cm 2 and 8.5 × 10 -17 cm 2 , at 200 eV, respectively. The rotational temperatures of CN(X, v = 0) from both molecules are 10000 ± 4000 K, assuming a Boltzmann distribution. © 1987.
  • Fast conductivity signals produced by pulsed laser photoionization of pyrene in non-polar hydrocarbon solvents, Sunao Yamada, Sadanori Yoshida, Hirofumi Kawazumi, Toshihiko Nagamura, Teiichiro Ogawa, Journal of Electroanalytical Chemistry, 122, 391 - 394, Dec. 13 1985
    Summary:The time profile of the conductivity signal of pyrene in non-polar hydrocarbon solvents consists of a fast signal (first few milliseconds) and a slow signal (after milliseconds). The fast signal is correlated with the electron mobility and is assigned to the displacement current and the electron drift. © 1985.
  • Fast conductivity signals produced by pulsed laser photoionization of pyrene in non-polar hydrocarbon solvents, Sunao Yamada, Sadanori Yoshida, Hirofumi Kawazumi, Toshihiko Nagamura, Teiichiro Ogawa, Chemical Physics Letters, 122, 391 - 394, Dec. 13 1985
    Summary:The time profile of the conductivity signal of pyrene in non-polar hydrocarbon solvents consists of a fast signal (first few milliseconds) and a slow signal (after some milliseconds). The fast signal is correlated with the electron mobility and is assigned to the displacement current and the electron drift. © 1985.
  • Isotope effects in the production of H*(n = 4) and D*(n = 4) in e-HD collisions, Keiji Nakashima, Hirofumi Kawazumi, Teiichiro Ogawa, Chemical Physics, 96, 447 - 452, Jul. 01 1985
    Summary:The lineshape and intensity of Balmer-β emission produced in e-HD collisions were measured and ratios of the emission cross sections of H* and D* (n = 4) were obtained in order to study the dynamics of hydrogen dissociation. At an electron energy of 25 eV, there is a weak isotope effect; σ D /σ D is = 1.1 This isotope effect decreases with increasing energy below 40 eV, and it increases again above 40 eV. Thus, it can be concluded that a slow group (threshold energy at ≈ 17 eV) and a fast group (threshold energy at 40-45 eV) present an effect, σ D ≥ σ H for both groups. This finding is correlated with a splitting of the dissociation limit and a coupling of the dissociative states. © 1985.
  • Translational energy distributions of the excited nitrogen atom produced by electron-impact dissociative excitation of nitrogen molecules, Teiichiro Ogawa, Shigeki Ishibashi, Shigeki Ishibashi, Junichi Kurawaki, Junichi Kurawaki, Hirofumi Kawazumi, The Journal of Chemical Physics, 82, 1920 - 1923, Dec. 01 1984
    Summary:The Doppler line shapes of atomic nitrogen emission (4p 2 S 1/2 -3s 2 P 3/2 : 4935.12 Å) were measured precisely with a Fabry-Perot interferometer at a resolution of 0.015 Å. The translational energy distributions of N* were calculated and found to be similar with those of N + and N(HR). There are three major components of N*; their peaks of the translational energy distribution and threshold energies are (1) 0.1-1.3 and 23.0 eV, (2) 2.8-3.0 and 29 eV, and (3)∼5 and 38-44 eV, respectively. The first component is produced by dissociative excitation through Rydberg states converging to the C state of N 2 + . © 1985 American Institute of Physics.
  • Production of the excited hydrogen atom (n = 4) by controlled electron impact on methanol, Teiichiro Ogawa, Shigeki Ishibashi, Hirofumi Kawazumi, Journal of Physical Chemistry, 88, 1662 - 1665, Dec. 01 1984
    Summary:Dissociation of methanol for the formation of the excited hydrogen atom (n = 4) from the methyl and the hydroxyl groups has been investigated by precise measurements of the shapes and intensities of the Balmer β line. The translational energies of H* and D* are 1.4-3.1 eV, indicating no isotope effect. Their threshold energies are 18.2-18.5 eV, indicating no significant difference for both groups. The relative scission probabilities of the C-H and O-H bonds and the isotope effect in bond dissociation depend on electron energies: C-H/C-D = 0.70-0.91, O-D/O-H = 0.41-0.59, C-D/O-D = 0.69-1.08, and C-H/O-H = 0.55. These results and an analysis based on a quasi-equilibrium theory suggest that the vibrationally excited Rydberg states converging to the (σ OH ) -1 ionized state are important intermediates for the formation of the excited hydrogen atom near the threshold energy. © 1984 American Chemical Society.
  • Translational energy distribution of the excited hydrogen atom (n=4) produced in electron-benzene collisions, Hirofumi Kawazumi, Junichi Kurawaki, Teiichiro Ogawa, Bulletin of the Chemical Society of Japan, 57, 1687 - 1688, Jun. 01 1984
  • Excitation to symmetry forbidden vibronic levels in the 1B2u state by controlled electron impact on benzene, Hirofumi Kawazumi, Takayuki Oomori, Naoki Yamani, Teiichiro Ogawa, Chemical Physics Letters, 106, 351 - 353, Apr. 27 1984
    Summary:The 1 B 2u - 1 A 1g fluorescence emission of benzene excited by controlled electron impact was measured in the 14 - 100 eV region. The optically forbidden 6° levels were preferentially, excited. This indicates that a non-dipole transition takes place under low-energy electron-molecule collisions. © 1984.
  • Fluorescence quenching in liposomal membranes. Exciplex as a probe for investigating artificial lipid membrane properties, Koji Kano, Hirofumi Kawazumi, Teiichiro Ogawa, Junzo Sunamoto, Journal of Physical Chemistry, 85, 2204 - 2209, Dec. 01 1981
    Summary:Fluorescence quenching of pyrene and pyrenedecanoic acid (PyDA) by various aromatic amines, such as N,N-dimethylaniline (DMA), N,N-dicetylaniline (DCA), and p-N,N-dimethylanilinesulfonate (DMAS), has been investigated in dipalmitoylphosphatidylcholine (DPPC) liposomes below and above a gel-liquid crystalline phase transition temperature (T c ). Below T c of the membranes, nonexponential fluorescence decay and nonlinear Stern-Volmer lines were observed when DMA was used as a quencher. These findings were interpreted in terms of the continuum theory for two-dimensional diffusion-controlled reactions. The lateral diffusion coefficients (D) in DPPC lipid bilayers below T c were found to be 1.6 × 10 -8 cm 2 /s for the pyrene-DMA system and 1.3 × 10 -8 cm 2 /s for the PyDA-DMA system. Above T c of the membranes, the fluorescence quenching of pyrene and PyDA by DMA obeyed the simple Stern-Volmer equation without a transient-effect term, indicating the high mobility of fluorophore and quencher molecules in lipid bilayers that are in a liquid cyrstalline state. In DPPC lipid bilayers above T c , the lateral diffusion coefficients of the pyrene-DMA and PyDA-DMA systems were 4.7 × 10 -7 and 3.1 × 10 -7 cm 2 /s, respectively. On the basis of data on fluorescence quenching via exciplexes, dynamic behavior of probes in liposomal membranes is discussed. © 1981 American Chemical Society.
  • Steady-state and time-resolved fluorescence studies on energy transfer in anionic surfactant membranes, Koji Kano, Hirofumi Kawazumi, Teiichiro Ogawa, Journal of Physical Chemistry, 85, 2998 - 3003, Dec. 01 1981
    Summary:Extremely efficient singlet-singlet energy transfer from pyrene to proflavin has been observed in dicetyl phosphate membrane suspensions. The acceptor-concentration dependence on the energy-transfer efficiency and the nonexponential decay curves of pyrene fluorescence were interpreted in terms of the theory of two-dimensional energy transfer without effect of diffusion. The effects of the membrane structure on the energy-transfer probability have been discussed. © 1981 American Chemical Society.
  • Fluorescence quenching of pyrene and pyrenedecanoic acid by various kinds of N,N-dialkylanilines in dipalmitoylphosphatidylcholine liposomes, Koji Kano, Hirofumi Kawazumi, Teiichiro Ogawa, Junzo Sunamoto, Chemical Physics Letters, 74, 511 - 514, Jan. 01 1980
    Summary:Fluorescence quenching of pyrene and pyrenedecanoic acid by various kinds of anilines has been studied in dipalmitoylphosphatidylcholine liposomes in gel phases. N,N-dimethylaniline and p-isopropyl-N,N-dimethylaniline caused anisotropic diffusional quenching, while N,N-dicetylaniline, a less mobile quencher, predominantly caused static quenching. These data suggested the location sites of both pyrenes and anilines in the membranes. © 1980, All rights reserved.

Books etc

  • Progress in Sustainable Energy Technologies Vol II, Creating Sustainable Development, KAWAZUMI Hirofumi, Contributor, Chapter 34, “High-Performance Recycling System for Waste Plastics Using Raman Identification”, Springer (SPi Global),   2014

Conference Activities & Talks

  • Dynamics of Solution Surface by Multi Photon Ionization Technique,   2001 01
  • Home Page of Center for Environmental Research and City Planning for NOGATA and its utilization for Environmental Education,   2001 06
  • Absorption spectra of adsorbed chelates on liquid-liquid interface,   2001 07
  • Determination of dissociation constant of pyrene compounds by fluorescence spectra shift,   2001 07
  • Chelate formation mechanism at liquid-liquid interface by total reflection induced thermal lens,   2001 08
  • Spectrum-based discrimination of microparticles labeled different kinds of rhodamine dyes by using a fluorescence imaging microscope,   2001 08
  • Microscopic chemical imaging for species-selective determination of rhodamine dyes adsorbed on microparticles,   2001 08
  • Near-Infrared Absorption Photometry for Water by Using a Semiconductor Laser,   2001 08
  • Monitoring complex dissociation reactions by short and micro capillary electrophoresis,   2001 08
  • Characterization of fluidic behavior in a microchannel,   2001 09
  • Quantitative analysis of test papers by using a personal computer and scanner system, 9th Beijing conference and exhibition on instrumental analysis (Beijing),   2001 10 , 9th Beijing conference and exhibition on instrumental analysis (Beijing)
  • Microscopic chemical imaging for species-selective determination of rhodamine dyes adsorbed on microparticles,   2001 11
  • Monitoring complex dissociation reactions by short and micro capillary electrophoresis,   2001 11
  • Near-Infrared Absorption Photometry for Water by Using a Semiconductor Laser,   2001 11
  • Effect of microchannel system on trypsin-catalyzed reaction,   2002 11
  • Compact and Multiple Surface-Plasmon-Resonance Immunosensor for Sub-ppblevel Small Molecules,   2003 10
  • Visualization of Fluidic and Reaction Dynamics in Microchannels,   2003 10
  • Preparation of CdSe nanocrystals in a Microreactor and their Particle Growth Kinetics and Photoluminescenceanalysis,   2003 12
  • Analysis of fluidic behavior and reaction dynamics in microreactor by simple visualization procedures, 32nd FACSS,   2005 , 32nd FACSS
  • adsorption control of gold nanorods modified with aminohexanethiol on a glass surface, PACIFICHEM 2005,   2005 , PACIFICHEM 2005
  • Rapid synthesis of gold nanostructures by microwavepolyol method, PACIFICHEM 2005,   2005 , PACIFICHEM 2005
  • CEPA for Biodiversity,   2011 08

Research Grants & Projects

  • Laser-Based Detector for Capillary Electrophoresis
  • Development of NIR Semiconductor Laser-Based Detector
  • Characterization of Interface by using Laser Spectroscopy