イオン対の固相抽出に及ぼす水中の微量の溶媒の効果

概要

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It was found that a low concentration of organic solvent dissolved in the aqueous phase remarkably enhances the ion-pair extraction onto as solid-phase. The ion-pair distribution between solid and aqueous phases was studied in the presence of organic solvent dissolved in the aqueous phase. The magnitude of the extraction was expressed by the extraction constant (K_<ex>) defined as : K_<ex>=[C^+・A^-]_s/ {[C^+][A^-]} where C^+ and A^- denote the cation and anion studied, and the subscript s expresses the solid phase. Bis [2-(5-chloro-2-pyridylazo)-5-diethylaminophenolato]cobalt (III) ion and dodecanesulfonate ion were the cation and anion studied. A cellulose nitrate membrane filter and octadecyl modified silica gel (ODS) were studied as the solid phase. Dissolved organic solvents, nitrobenzene, o-xylene and benzene at 2〜8×10^<-3> mol dm^<-3>in the aqueous phase, enhanced the distribution of the ion pair onto the solid-phases. In particular, in the case of ODS, o-xylene and nitrobenzene gavc 2.5 and 2.2 greater log K_<ex>values, respectively, compared with those in the absence of the solvents. The drastic enhancement of extracting power onto the solid-phase by the dissolved organic solvent will be useful for the improvement of collection efficiency in preconcentration for trace analysis.
社団法人日本分析化学会の論文
1995-04-05