BUNSEKI KAGAKU
Print ISSN : 0525-1931
Volume 53, Issue 10
Displaying 1-19 of 19 articles from this issue
Account
  • Munetaka OYAMA
    2004 Volume 53 Issue 10 Pages 1105-1118
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    For the purpose of elucidating and understanding the reaction dynamics of short-lived intermediates formed in the solution phase, it is very important to carry out detection and kinetic analysis in a homogeneous solution without being interfered by concentration gradients, which are usually unavoidable in electrochemical and pulse-radiolysis methods. Our group is proposing an electron-transfer stopped-flow (ETSF) method for the spectroscopic detection and reaction analysis of short-lived ion radicals formed in aprotic solvents. In the ETSF method, e.g., short-lived cation radicals are formed via electron transfer reactions with stable cation radicals in the mixing part of a stopped-flow apparatus, so that any changes in the absorption spectra are observed in an optical cell after stopping the solution flow. In this account, the principle and actual procedures of the ETSF method are described first. Then, some successful results obtained using the ETSF method in observing the absorption spectra and analyzing the reaction mechanisms are summarized for the reactions of poly-aromatic cation radicals and aromatic amine cation radicals. The former includes anthracene and pyrene derivative cation radicals formed in acetonitrile, and the latter includes aniline, N-methylaniline, N,N-dimethylaniline and diphenylamine derivative cation radicals formed in acetonitrile. Finally, as interesting examples that the ETSF analysis cannot give straightforward results, time-resolved absorption spectra observed for the oxidation processes of N,N-dimethyl-o-toluidine and N,N-dimethyl-m-toluidine in acetonitrile are shown and discussed.
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Research Paper
  • Kohshi KASHIMA, Minoru UMEDA, Akifumi YAMADA
    2004 Volume 53 Issue 10 Pages 1055-1059
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    We have studied the influence of Clion for methanol electrooxidation in direct methanol fuel cells (DMFCs) by using a Nafion-modified Pt microelectrode(φ 50 μm). The microelectrode was employed to form a uniform-thick Nafion overlayer on the Pt surface. Hg/Hg2SO4 and Pt wire were used as a reference and a counter electrode, respectively. Current-potential curves were measured in a 0.5 M H2SO4 or 0.5 M CH3OH + 0.5 M H2SO4 solution. KCl was added into the solution at arbitrary rates. As a result, we have observed that (i)Clion adsorbs on the Pt surface, which prohibited not only Pt oxide formation but also Methanol electrooxidation. The Nafion membrane prevented Cladsorption, because of it’s cation exchange property. (ii)However, a small part of Clion was able to pass throughout Nafion membrane and adsorbs on the Pt surface. (iii) It has been known that a strong correlation exists between Pt surface oxide formation and methanol electrooxidation at a Pt electrode.
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  • Kousuke ISHIDA, Masaaki HARADA
    2004 Volume 53 Issue 10 Pages 1061-1065
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    The adsorption and desorption of chromium(VI) ion from aqueous solution on active carbons were studied. The adsorption rate of Cr(VI) ion was measured at various pH values, and was proved to be proportional to its concentration. The chemical species and their respective adsorption rate constants were determined from the pH dependence of the adsorption rate. A desorption experiment of adsorbed Cr(VI) was performed by HNO3 or NaOH. Only Cr(III) ion was desorbed by HNO3, while both Cr(III) and Cr(VI) ions were desorbed by NaOH. This shows that Cr(VI) adsorbed on active carbon was reduced to Cr(III) and then Cr(III) was desorbed. The results of Freundlich plot supported the adsorption/desorption mechanism presumed from the experimental results mentioned above.
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  • Kaori NAKAMURA, Takuya SHIMOSAKA, Katsumi UCHIYAMA, Toshiyuki HOBO
    2004 Volume 53 Issue 10 Pages 1067-1072
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    We monitored the diffusion of Cu2 + into a phospholipid bilayer containing a metallochromic indicator, 1-(2-pyridylazo)-2-naphthol (PAN), by using total internal reflection with thermal lens spectroscopy (TIR-TLS), which is a non-destructive and surface-selective spectrometry. When Cu2 + entered into the bilayer, a formation of Cu-PAN chelate resulted in decrease of the absorbance at the wavelength of the excitation beam. The decrease was detected by TIR-TLS. We measured five kinds of bilayer samples, whose molar ratios of two phospholipids, 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) and 1-stearoyl-2-oreoyl-sn-glycero-3-phosphatidylserine (SOPS), were 10 : 0, 7 : 3, 5 : 5, 3 : 7, 0 : 10. In the case of a bilayer whose ratio of DOPC to SOPS was 7 to 3, the signal intensity showed an obvious decrease compared to a blank. On the other hand, there no significant change was observed in the case of other samples. Several attempts using a 7 : 3 bilayer revealed a non-reproducible incorporation of Cu2 + into the lipid. We also proved the effect of a counter ion by comparing sulfate ion and chloride ion.
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  • Natsuki HIRA, Nobuo TANAKA, Ken HOSOYA
    2004 Volume 53 Issue 10 Pages 1073-1077
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    We have prepared a polymer-based stationary phase modified with thiacalix[4]arene. Thiacalix[4]arene (5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrahydroxy-2,8,14,20-tetrathiacalix[4]arene) is an amphiphilic molecule, that consists of four p-tert-butylphenol-related groups cyclically connected through a single sulphur atom between each pair. It has a high-electron density area formed by hydroxyl groups and sulfur atoms. We studied the applicability of this interesting compound as a selector because of its specific feature for high-performance liquid chromatography (HPLC). First of all, uniformly sized polymer particles were prepared using ethylene glycol dimethacrylate (EDMA) as a cross-linker through a multi-step swelling and polymerization method. Methacrylic acid (MAA) was introduced onto the surface of polymer particles through an invented modification method. Thiacalix[4]arene was cavalently bonded to MAA using 1,4-dibromo-butane as a spacer to reduce any steric hindrance of MAA on the surface of the polymer particles. The prepared polymer-based stationary phase was evaluated with HPLC. It provided a specific chromatographic retention behavior only for catechol among positional isomers of xylene, cresol, and benzene-diol. Catecholamine showed a specific chromatographic retention behavior as catechol.
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  • Keiji YOSHIMURA, Junko INOTSUME, Ryoei KIKUCHI, Toru OZEKI, Masahiro K ...
    2004 Volume 53 Issue 10 Pages 1079-1085
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    Rain and fog samples were collected from the Akita Hachimantai mountain range between June and September, 2000. By classifying the course of transport of the air mass by 72 h back trajectory at the 850 hPa level, when the air masses were transported from the Korean Peninsula or near China, the ion concentrations were shown to be very high by nss-SO42−. After 8 July, 2000, when a volcano erupted at Miyake Island, a high [nss-SO42−]/[NO3] ratio was observed in some samples. It was concluded that the samples had been influenced by volcanic gas from Miyake Island using 72 h back trajectory at the 850 hPa level.
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  • Hiromi SAWADA, Tomoki NOMAGUCHI, Kenji OKITSU, Norimichi TAKENAKA, Hir ...
    2004 Volume 53 Issue 10 Pages 1087-1091
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    In September 2001, January 2002 and December 2003, we measured peroxy radicals (RO2) in urban polluted air using the Peroxy Radical Chemical Amplification (PERCA) method. Since the observation site in 2003 was much affected by automobile exhaust, during the observatiion the average NOx concentration exceeded 90 pptv. In this observation, the daytime RO2 cancentration was similar to that at other observation sites, and in the reported literature. However, in 2003 measurement, the nighttime RO2 concentration was found to be below the detection limit (3.5 pptv) most of the time. This result was different from the other two measurements. Though a difference was not seen in the RO2 concentration in the observations of 2001 and 2002, the average O3 concentration was very different. These results obtained in this study for urban polluted air can not be explained based on general knowledge about atmospheric chemistry, especially concerning the correlation between the RO2 and O3 concentrations.
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  • Junichi SUGIYAMA, Hiroyuki HANIHARA, Kosuke TANAKA, Kuniaki ADACHI
    2004 Volume 53 Issue 10 Pages 1119-1123
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    Cationic polymers in hair shampoo form a complex with an anionic surfactant, and adhere to the hair when the shampoo is rinsed. This complex plays an important role in the feeling of the rinse for user, and in the conditioning provided by the shampoo. Therefore, the amount and molecular weight information of the cationic polymer is important for examining both the performance and quality control. Nevertheless, no accurate method has yet been established for analyzing the cationic polymers used for hair shampoo. We used SEC-MALLS-RI (size-exclusion chromatography with a multiangle laser light-scattering detector and refractive index detector) to examine the cationic cellulose [cellulose,2-hydroxyethyl 2-{2-hydroxy-3(trimethylammonio)propoxy}ethyl 2-hydroxy-3-(trimethylammonio)propyl ether,chloride] (CC) used for hair shampoo. In this analysis, we used a column in which the stationary phases were based on vinyl polymer and a 0.3 M NaClO4 solution. The chromatogram was clear and precise, and we verified that the CC was separated by the size of MALLS and RI(plot of molecular weight vs. retention time). There was no adsorption between the CC and the column stationary phases, and the calibration curves showed good agreement with each other. It was determined that any grade of CC could be used as a standard. We conclude that the present technique is an accurate method of measuring the amount of CC and determining its absolute molecular weight used for hair shampoo.
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  • Ryo KOIKE, Shoichi JO, Mikiko AZUMA, Tatsushi WAKISAKA
    2004 Volume 53 Issue 10 Pages 1125-1131
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    A method based on proton nuclear magnetic resonance (1H-NMR) using an internal standard (IS) was developed for the determination of anionic and cationic surfactants. In this study, potassium hydrogen phthalate or sodium 3-trimethylsilyl-2,2,3,3-tetradeutero propionic acid was added to a sample solution as an IS for the determination, and surfactants were determined by using integrations of IS and diagnostic surfactant resonances in the 1H-NMR spectrum. This method is suitable for the determination of surfactants because there is no surfactant whose contribution corresponds completely with each analyte in many cases. By optimizing the acquisition parameters and solvent, various surfactants were determined under the same condition. Each 1H-NMR spectrum was obtained within 5 min and the detection limit given for sodium lauryl sulfate, a typical anionic surfactant, was approximately 60 ppm. The results obtained for commercial surfactants were in good agreement with those of the JIS titration method (Epton method) and the relative standard deviations were 0.12∼0.44%.
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  • Ryo KOIKE, Shoichi JO, Mikiko AZUMA, Tatsushi WAKISAKA
    2004 Volume 53 Issue 10 Pages 1133-1138
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    A method based on proton nuclear magnetic resonance (1H-NMR) using an internal standard (IS) was developed for the determination of amphoteric and nonionic surfactants. This method does not require a tedious pretreatment, and surfactants are determined by using integrations of IS and diagnostic surfactant resonances in the 1H-NMR spectrum. By optimizing the combination of solvent and IS, various surfactants were determined under the same condition. Each sample was measured within 5 min, and the detection limit given for lauryl dimethylamine oxide, a typical amphoteric surfactant, was 8.0 ppm. The results obtained for commercial surfactants were in good agreement with those of the conventional methods (gravimetric method etc.) and the relative standard deviations were 0.13∼0.36%. Furthermore, we confirmed that the proposed method was applicable to the determination of nonionic surfactants not containing an ethylene oxide chain, such as glycerol fatty acid ester and fatty acid alkanolamide.
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  • Yuichi HORII, Takao KATASE, Yun-Seok KIM, Nobuyoshi YAMASHITA
    2004 Volume 53 Issue 10 Pages 1139-1147
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    Because technical nonylphenol (NP) preparations are constituted by complex isomers and impurities, wide varieties of isomer composition were found in the environmental matrix. Since there is not sufficient information concerning isomer specific quantification, the currently available analytical method (e.g. JIS K 0450-20-10, 2002) of NP is applicable to determine only the total concentration, which is calculated by summing three to eight peaks in a gas-chromatogram. Hence, reliable analytical methods for each isomer are necessary for a risk assessment and source determination of NP, which is one of the most important endocrine disruptors. In this study, we developed an isomer-specific quantification method of thirteen individual NP isomers based on relative response factor (RRF) quantification by gas-chromatograph mass spectrometry in combination with steam distillation extraction of non-filtered water (SD-RRF method). The remarkable points concerning the SD-RRF method are that the extraction efficiencies of chemicals using steam distillation correspond to their boiling point, not only polarity. This method enables a reliable identification/quantification of thirteen isomers of NP by using RRF (by using a suitable ion to quantify; m/z 107, 121, 135, 149, 163, 177, 191 and 220). We validated the SD-RRF method for selected water samples in Arakawa River and Hanamigawa River around Tokyo Bay; a significant variation (3.8 to 15%) of the isomer composition was found in environment water samples.
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Technical Paper
  • Yuka SATO, Kimito SAKAI, Makiko TAMAOKI, Miyuki TAKENAKA
    2004 Volume 53 Issue 10 Pages 1149-1155
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    Some airborne organic contaminants in clean rooms for semiconductor manufacturing are unstable with respect to heating, and are easily adsorbed by silicon wafers. Accordingly, in order to measure their concentration, we developed a method that uses silicon powder adsorbent and solvent desorption-GC/MS analysis. Various methods of desorption were examined, and it was found that the most efficient method was desorption by passing n-hexane through the adsorbents. This method was compared with thermal desorption using standard solutions of di(2-ethylhexyl)phthalate (DEHP) and 2,6-di-buthylhydroxyhydroxyphenol (BHT). Using these solutions, which are unstable against heating, compounds could be detected without any alteration by this method, although altered compounds from DEHP and BHT were detected by thermal desorption. The detection limits of DEHP, dibuthylphthalate (DBP) and di(2-ethylhexyl)adipate (DEHA) by this solvent desorption method were 2 ng/m3, 2 ng/m3 and 0.6 ng/m3 respectively. By applying this method to the evaluation of clean-room air, DEHP, DBP and DEHA were detected, ranging in concentration from 16 to 80 ng/m3.
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Note
  • Yusuke FUJIMOTO, Tsuyoshi FUJIMOTO, Takako YAMAGUCHI, Yoshikazu FUJITA
    2004 Volume 53 Issue 10 Pages 1093-1096
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    A spectrophotometric method for the determination of p-quinones was established with N,N-diethy-1,4-phenylenediamine. In the determination of 2,3-dimethoxy-5-methyl-1,4-benzoquinone (DMBQ), Beer’s law was obeyed in a concentration range of 0.1∼1.5 μg/ml of DMBQ. The apparent molar absorptivity was 1.1 × 105 l mol− 1 cm− 1 at 552 nm. The relative standard deviation for six replicate determinations for 0.18 μg/ml was 0.48%.
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  • Noriko KITAMURA, Akira KOTANI, Fumiyo KUSU
    2004 Volume 53 Issue 10 Pages 1097-1100
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    A disposable voltammetric cell using three pencil leads as working, reference, and counter electrodes was developed for determining titratable acidity, i.e. the acid content in wood-vinegar. The materials of the pencil leads were graphite-reinforcement carbons (GRCs). The voltammetric detection of acids was based on the electrochemical reduction of quinone, 3,5-di-tert-butyl 1,2-benzoquinone (DBBQ), in an unbuffered solution. Acetic acid in an unbuffered ethanol-water (3 : 2, v/v) solution of DBBQ gave rise to a new peak (termed the prepeak) on a voltammogram at more positive potentials than that corresponding to the normal reduction peak of DBBQ. The prepeak current was found to be proportional to the acetic acid concentration from 0.05 to 2.7 mM with a correlation coefficient of 0.999. The cell-to-cell reproducibility for 1 mM acetic acid was evaluated with five individual disposable cells. The RSD of the prepeak current and potential were 2.0% and 1.5%, respectively. The titratable acidity in six wood-vinegar samples was determined by voltammetry using disposable cells, and was compared with that of the titratable acidity determined by the conventional potentiometric titration method. We then observed the results by both methods, and found a correlation coefficient of 0.999. As such, the voltammetry using disposable-cell required only two thousandth of the volume of a wood-vinegar sample for the titration method. The present method was superior to the potentiometric titration method in terms of facility, environment-friendly, and economy, and thus a sensor using the present cell would be useful for routine work in the quality control of wood-vinegar.
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  • Akihiro MATSUMOTO, Tadashi SHIOZAKI, Taketoshi NAKAHARA
    2004 Volume 53 Issue 10 Pages 1157-1161
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    An annular-shaped high power nitrogen microwave induced plasma atomic emission spectrometry with a hydride generation method is described for the determination of lead in steel. Under the optimized experimental conditions, the best attainable detection limit at the Pb I 368.347 nm lines was 35.2 ng ml−1 for lead. The linear dynamic range for lead was 100 to 30000 ng ml−1 in concentrations. The presence of several diverse elements was found to cause a more or less depressing interference with the proposed technique. Of the several oxidizing agents examined, hydrogen peroxide for lead was found to be the most preferable to oxidize lead prior to hydride generation. When lead in two certified reference materials of steel was determined, a large amount of Fe(III) in the solution caused a severe depressing interference, while the presence of Fe(II) showed little or no significant interference. Of the several interference-releasing agents examined, L-ascorbic acid was found to be the most preferable to pre-reduce Fe(III) to Fe(II). The concentrations of lead in steel were determined by the use of the standard additions method. The results obtained by this method were in good agreement with their certified values.
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  • Yoshio KUMOOKA
    2004 Volume 53 Issue 10 Pages 1163-1166
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    A mixture of N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and trimethylchlorosilane (TMCS) (99 : 1) is a highly sensitive derivatization reagent for carboxylic acid by gas chromatography/mass spectrometry (GC/MS), and Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) of poly(acrylic acid) (PAA) at 500 °C in the presence of the above silyl reagent was conducted. It was found that the peak height of the trimethylsilyl derivative of acrylic acid (AA-TMS) was about ninety-five times that of the peak height of acrylic acid, which is one of the pyrolysates of PAA, without any derivatization reagent. The mechanism for the formation of AA-TMS was considered to be as follows. The carboxyl group of PAA and the mixture of BSTFA and TMCS reacted rapidly at room temperature. The reaction product was then pyrolyzed and AA-TMS was liberated.
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Technical Letter
Analytical Report
  • Shin KUMAKURA, Miho TANAKA, Susumu HASHIMOTO, Masaru MAEDA
    2004 Volume 53 Issue 10 Pages 1101-1104
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    To obtain current data of lanthanoides and heavy metals in Sagami Bay sediment, a sediment sample was collected at a location 13 km off shore. The surface sediment (0∼1 cm) was decomposed with HNO3, HF and HClO4. The detection of these elements was achieved by inductively coupled plasma mass spectrometry. These data will be used as a comprehensive baseline data for future environmental-impact studies, such as on the discharge of accumulated sands and sediments from the dam in Sagami River. A sediment reference material, MESS-3, was also analyzed to verify the present analytical method. The obtained value for heavy metals, such as Cr and As, were in good agreement with the certified values. The concentrations of lanthanoides in MESS-3 were also presented.
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