Long-Time Evaluation of Solid-State Composite Reference Electrodes

Slim Blidi; Kim Granholm; Tomasz Sokalski; Zekra Mousavi; Andrzej Lewenstam; Ivo Leito; Johan Bobacka

doi:10.3390/membranes12060569

Long-Time Evaluation of Solid-State Composite Reference Electrodes

Membranes (Basel). 2022 May 30;12(6):569. doi: 10.3390/membranes12060569.

Authors

Slim Blidi¹, Kim Granholm¹, Tomasz Sokalski¹, Zekra Mousavi¹, Andrzej Lewenstam^{1

2}, Ivo Leito³, Johan Bobacka¹

Affiliations

¹ Johan Gadolin Process Chemistry Centre, Laboratory of Molecular Science and Engineering, Åbo Akademi University, Henriksgatan 2, FI-20500 Turku-Åbo, Finland.
² Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow, Poland.
³ Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia.

Abstract

In this study, the performance and long-time evaluation of solid-state composite (SSC) reference electrodes were investigated. The stability of all the SSC reference electrodes was continuously monitored by using potentiometry and electrochemical impedance spectroscopy methods over a period of several months. A multi-solution protocol was used to study the influence of the ionic strength of the sample solution, ion charge, and mobility, and the sample pH values on the performance of the reference electrodes. The SSC reference electrodes were used in the calibration of commercial indicator electrodes for different ions at different temperatures. The concentrations of K⁺, Na⁺, Ca²⁺, and Cl^- ions and pH values were measured in river water samples at different temperatures using the SSC reference electrodes. The obtained results for the same samples were compared with the results given by an independent laboratory specialized in routine water analyses. The agreement between the results was very good and even better than the case where commercial reference electrodes were used. Our study showed that the SSC reference electrodes exhibit good long-term stability and excellent performance, both in the calibrations and analyses of environmental samples.

Keywords: long-time evaluation; reference electrode; solid-state.

Grants and funding

Slim Blidi gratefully acknowledges the support from the EU via the Excellence in Analytical Chemistry (EACH) Erasmus Mundus programme (Agreement No. 2014-2613).