ID | 19905 |
Eprint ID | 19905
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FullText URL | |
Title Alternative | Analysis of ion-association reactions between quaternary ammonium ions and monovalent organic anions by capillary zone electrophoresis
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Author |
Wada, Eiko
Motomizu, Shoji
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Abstract | Ion-association reactions in an aqueous solution between monovalent aromatic anions and quaternary ammonium ions were analyzed by means of the electrophoretic mobility. The electrophoretic mobility of analytes, such as phenolate, benzoate, benzenesulfonate, 1, 3-benzenedisulfonate, 1- and 2- naphtholate, 1- and 2- naphthalenecarboxylate, and 1-and 2- naphthalenesulfonate, was obtained by capillary zone electrophoresis. The electrophoretic mobility of analyte anions decreased with increasing the concentrations of the quaternary ammonium ions added in migrating solutions. The change in the electrophoretic mobility was analyzed to obtain the ion-association constants (K(ass)) by a nonlinear least-squares analysis method, as well as linear-square analysis methods. The obtained ion-association constants were larger in the anions possessing naphthalene ring than in those possessing benzene ring. The values of K(ass) became larger when more bulky cations were used as a pairing ion, indicating that the hydrophobicity of ions contributed to the ion associability. The ion associablities of β-substituted naphthalene isomers were larger than those of the α-substituted type, which agreed with the acid-dissociation property of the anions. The difference in the K(ass) values among functional groups was small, compared with ion-pair extraction constant (K(ex)) of the ion associates.
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Abstract Alternative | 水溶液内におけるイオン会合反応を調べる方法として,イオンの電気泳動移動度の変化を利用する方法を開発し,一価-一価イオン間の比較的弱いイオン会合反応を解析することに初めて成功した.イオン会合系として,ベンゼン環,ナフタレン環を有する9種類の一価有機酸イオン,二価の1,3-ベンゼンジスルホン酸イオンと,第四級アンモニウムイオンとの間での反応を検討した.アルカリ性(pH11.7)の泳動液中におけるこれら陰イオンの電気泳動移動度は,泳動液に添加した第四級アンモニウムイオン濃度の増加に伴って低下した.この移動度の変化は,キャピラリー電気泳動法で求めた.移動度の変化を非線形最小二乗法及び幾つかの線形法により解析し,各々のイオン会合定数を得た.得られたイオン会合定数はナフタレン骨格を有するものがベンゼン骨格を有するものよりも大きく,かさ高い対陽イオンを用いた場合に大きいことから,疎水性の寄与が示唆された.又,ナフタレン環を持つ有機酸イオンの異性体では,α-位置換体よりもβ-位置換体のほうがイオン会合定数が大きい.これは酸解離定数(pK(a))の大きさの序列と一致した.置換基の種類によるイオン会合性の差は,イオン会合抽出における差よりも小さいことが分かった.イオン会合抽出の結果も考え合わせると,フェノレート,ベンゾエートイオンでは,水溶液内イオン会合の寄与がかなり大きいことが分かった.
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Keywords | ion association
aqueous solution
capillary zone electrophoresis
quaternary ammonium ions
aromatic anions
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Published Date | 1997-06-05
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Publication Title |
分析化学
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Publication Title Alternative | Bunseki Kagaku
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Volume | volume46
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Issue | issue6
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Publisher | 日本分析化学会
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Publisher Alternative | The Japan Society for Analytical Chemistry
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Start Page | 467
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End Page | 475
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ISSN | 0525-1931
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NCID | AN00222633
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Content Type |
Journal Article
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Official Url | http://www.journalarchive.jst.go.jp/japanese/jnlabstract_ja.php?cdjournal=bunsekikagaku1952&cdvol=46&noissue=6&startpage=467http://www.journalarchive.jst.go.jp/japanese/jnlabstract_ja.php?cdjournal=bunsekikagaku1952&cdvol=46&noissue=6&startpage=467
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language |
Japanese
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Copyright Holders | The Japan Society for Analytical Chemistry
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File Version | publisher
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Refereed |
True
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