ISSN:
1040-0397
Keywords:
Ferric ion
;
Potentiometry
;
Glass membrane
;
Ion-selective electrode
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A ferric ion-selective electrode based on the iron containing chalcogenide glass FexSe60Ge28Sb12(X = 1-10) was reinvestigated in order to optimize the electrode characteristics and to elucidate the mechanism of the potential determining process. By modifying the preparation procedure of the chalcogenide glass described in the literature and of the electrode configuration highly stable sensors were obtained. These sensors show super-Nernstian slopes of the calibration plots of about 65 mV/decade, selectivity coefficients of about 10-4for several heavy metal ions and a potential drift of 3-4 m V/h due to some slow corrosion process occuring at the electrode surface. Furthermore the data of impedance, cyclovoltammetric, and XPS experiments show that the conditioning process of the electrode leads to a modified surface layer which behaves like a specific ion exchanger for Fe3+ ions. In contact with a Fe3+ containing electrolyte, the exchange of Fe3+ ions between the electrolyte and the modified surface layer leads to the injection of holes from the surface layer into the bulk of the chalcogenide glass. Thus the fermi level of the material is shifted, causing the observed potential change.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/elan.1140071117
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