Towards reversibility of ion transfer across the interface between valinomycin membranes and aqueous electrolyte solutions

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Mikhelson KN, Bobacka J, Lewenstam A, Ivaska A
Publisher: MAIK NAUKA/INTERPERIODICA
Publication year: 2003
Journal: Elektrokhimiya / Russian Journal of Electrochemistry
Journal acronym: RUSS J ELECTROCHEM+
Volume number: 39
Issue number: 7
Start page: 771
End page: 776
Number of pages: 6
ISSN: 1023-1935


Abstract

Valinomycin-based potassium-selective membranes doped with potassium tetrakis(4-chlorophenyl)borate (KClTPB) or sodium tetrakis(4-fluorophenyl)borate (NaFTPB) are studied in KCl, NaCl, and CaCl2 solutions by potentiometric and electrochemical impedance methods. Before contact with KCl, membranes doped with NaFTPB provide Nernstian potentiometric response to Na+ ions, which is lost after conditioning the membranes in KCl. The membranes doped with KClTPB even before contact with KCl give no Nernstian response to Na+ ions. In CaCl2 solutions, none of the membranes provide a regular potentiometric response. Despite the difference in potentiometric behavior, the impedance spectra of the membranes are very similar in all solutions regardless of prior conditioning of the membranes. No evidence for a hindrance towards charge transfer processes is observed. The results suggest that the membrane/solution interface is reversible for interfering ions as well as for potassium, and the contamination of solutions with the latter is the sole reason for the lack of Nernstian response in the interfering electrolytes.

Last updated on 2020-26-02 at 04:25