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Titolo:
Ion-selective charge separation at the interfaces between surface-active crown ether-incorporated liquid membranes and aqueous sample solutions as studied by resonant optical second-harmonic generation
Autore:
Tohda, K; Umezawa, Y;
Indirizzi:
Univ Tokyo, Sch Sci, Dept Chem, Bunkyo Ku, Tokyo 1140033, Japan Univ Tokyo Tokyo Japan 1140033 ept Chem, Bunkyo Ku, Tokyo 1140033, Japan
Titolo Testata:
BUNSEKI KAGAKU
fascicolo: 12, volume: 47, anno: 1998,
pagine: 1027 - 1033
SICI:
0525-1931(199812)47:12<1027:ICSATI>2.0.ZU;2-0
Fonte:
ISI
Lingua:
JPN
Soggetto:
2ND-HARMONIC GENERATION; ORIENTATION; ELECTRODES;
Keywords:
molecular orientation; phase boundary potential; surface activity; detection limit; resonant optical second harmonic generation (resonant optical SHG); SHG active complex cation; liquid/liquid interface; potentiometry;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
10
Recensione:
Indirizzi per estratti:
Indirizzo: Tohda, K Univ Tokyo, Sch Sci, Dept Chem, Bunkyo Ku, Tokyo 1140033, Japan Univ Tokyo Tokyo Japan 1140033 Bunkyo Ku, Tokyo 1140033, Japan
Citazione:
K. Tohda e Y. Umezawa, "Ion-selective charge separation at the interfaces between surface-active crown ether-incorporated liquid membranes and aqueous sample solutions as studied by resonant optical second-harmonic generation", BUNSEKI KAG, 47(12), 1998, pp. 1027-1033

Abstract

Resonant optical second-harmonic generation (resonant optical SHG) at the interfaces between aqueous sample solutions and liquid membranes, based on ionophores with different surface activities was measured in order to investigate the influence of the surface activity of ionophores on ion-selectivecharge separation. As ionophores with different surface activities, but bearing the same crown ether moiety as a binding site for the Na+ ion, 4'-(p-octadecylbenzoateazo)phenoxymethyl-15-crown-5 (1) and 4'-(p-methylbenzoateazo) phenoxymethyl-15-crown-5 (2) were synthesized. The dependence of the SHG intensities on the polarization angle of the incident laser light showed that the average molecular orientations of ionophores 1 and 2 at the liquid/liquid interface were nearly equal to each other. When the concentration of Na+ ion in the aqueous sample solutions increased, increases in the SHG intensities were observed for both membranes based on ionophores 1 and 2. However, the SHG intensities based on ionophore 1 were stronger, suggesting that the surface activity of ionophore I is higher than that of ionophore 2. The change in the phase boundary potentials of the ionophore I-based membrane in contact with the aqueous Naf ion solutions was found to be larger than that of ionophore 2. An improvement in the potentiometric detection limit for Na+ ion was also shown for membranes based on surface-active ionophore 1. These results demonstrate that the extent of charge separation at the liquid/liquid interface, as observed by resonant SHG from primary ion complexes, is increased by using surface-active ionophores.

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Documento generato il 07/08/20 alle ore 07:19:02