All-solid-state ion-selective electrodes with conducting polymer transducer under conditions of galvanostatic polarization

Krzysztof Maksymiuk ,  Agata J. Michalska 

Warsaw University, Faculty of Chemistry, Pasteura 1, Warszawa 02-093, Poland

Abstract

All-solid-state potentiometric sensors with a conducting polymer based ion-to-electron transducer have become a promising alternative to well known internal solution ion-selective electrodes (ISEs) with solvent polymeric poly(vinyl chloride) (PVC) based membranes. Recently, considerable progress has been achieved in selectivity enhancement and lowering the detection limit of above mentioned solid-state sensors. Improvement of analytical parameters of ISEs can be also obtained by galvanostatic polarization with small applied currents (usually in the range of nA). Such currents affect ion fluxes, under favourable conditions reducing or eliminating primary ions release from the ion-selective membrane. This method is also a useful tool for studies on fundamental electrochemical properties of ion-selective electrodes, important for their analytical characteristic. This lecture shows limitations and possibilities of potentiometry with ion-selective electrodes under conditions of galvanostatic polarization. Criteria for improved linear response range, related to membrane and transducer composition as well as to magnitude and direction of applied current are discussed. Advantages of chronopotentiometric method to study ion fluxes related to the membrane composition and chemical reactivity of the polymeric transducer are presented. Some diagnostic criteria are proposed, relating the observed potential vs. time dependences with properties of the sensor and transport phenomena in the membrane and sample solution.

 

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Presentation: Keynote lecture at SMCBS'2007 International Workshop, by Krzysztof Maksymiuk
See On-line Journal of SMCBS'2007 International Workshop

Submitted: 2007-10-03 12:35
Revised:   2009-06-07 00:44