顕微吸光法によるアルコール-水系におけるオクタデシルシリルシリカゲル細孔内分配過程の評価  [in Japanese] Evaluation of the Distribution in Mesopores of ODS-Silica Gel in Alcohol-Water Solvent by Absorption Microspectroscopy  [in Japanese]

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Author(s)

    • 蛎崎 洋 KAKIZAKI Hiroshi
    • 筑波大学大学院数理物質科学研究科化学専攻 Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba
    • 中谷 清治 NAKATANI Kiyoharu
    • 筑波大学大学院数理物質科学研究科化学専攻 Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba

Abstract

アルコール-水混合溶媒中におけるオクタデシルシリル(ODS)シリカゲル細孔内分配過程に及ぼすアルコールのアルキル鎖長と混合比率の影響を,単一微粒子ごとの吸光分析により検討した.吸収スペクトルが周囲の媒体の極性と水素結合により変化するフェノールブルー(PB)をプローブ分子として用い,アルコール-水混合溶媒系においてODSシリカゲルにPBを収着させたところ,PBは細孔内におけるODS/溶液界面に吸着していることが分かった.PBの吸収極大波長の変化からODS/溶液界面近傍の極性と水素結合性を,PBの吸着係数の変化からODS相の極性を議論できることを示した.ODSシリカゲル/アルコール-水混合溶媒系におけるアルコール分子は,細孔内溶液相とODS相の両方の極性に影響を与え,アルキル鎖長の増加とともにODS相へのアルコール分子の分配の寄与が大きくなることを明らかにした.<br>

The sorption of phenol blue (PB), known as a solvatochromic dye, from an alcohol (methanol, ethanol, butanol or pentanol)-water mixture solvent into single spherical octadecylsilyl (ODS)-silica gel microparticles {particle diameter (<i>d</i>) of 20 ~ 60 μm, pore diameter of 12 nm} was investigated by absorption microspectroscopy. For ~ 0.5 vol% pentanol, ~ 0.5 vol% butanol or 1 vol% ethanol, the adsorption coefficient of PB in a single microparticle (<i>K</i><sub>ads</sub>), determined on the basis of the Langmuir isotherm, was much smaller than that for water although the relative permittivity of the mixture solvent was almost the same as that of water. Furthermore, the absorption maximum of PB in the microparticle (λ<sub>max</sub>) for the mixture solvent was slightly shifted from that for water. For 1 vol% methanol, both λ<sub>max</sub> and <i>K</i><sub>ads</sub> did not change compared with those for water. The results showed that for a mixture solvent of pentanol, butanol or ethanol the microscopic polarity in the ODS phase was larger and the polarity and hydrogen bonding in the vicinity of the ODS/solution interface were smaller than those for water because the alcohol molecules with the long alkyl chain length distributed in the ODS phase. Concerning the volume percentage of alcohol greater than ~ 5 vol%, on the other hand, λ<sub>max</sub> and <i>K</i><sub>ads</sub> significantly decreased with the increasing volume percentage of alcohol, revealing a decrease in the relative permittivity of the mixture solvent as well as changes in the microscopic polarity and hydrogen bonding.<br>

Journal

  • BUNSEKI KAGAKU

    BUNSEKI KAGAKU 54(6), 479-483, 2005-06-05

    The Japan Society for Analytical Chemistry

References:  14

Codes

  • NII Article ID (NAID)
    110002910089
  • NII NACSIS-CAT ID (NCID)
    AN00222633
  • Text Lang
    JPN
  • Article Type
    ART
  • ISSN
    05251931
  • NDL Article ID
    7399007
  • NDL Source Classification
    ZP4(科学技術--化学・化学工業--分析化学)
  • NDL Call No.
    Z17-9
  • Data Source
    CJP  NDL  NII-ELS  J-STAGE  NDL-Digital 
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