Long-Time Evaluation of Solid-State Composite Reference Electrodes

In this study, the performance and long-time evaluation of solid-state composite (SSC) ref-erence electrodes were investigated. The stability of all the SSC reference electrodes was continuouslymonitored by using potentiometry and electrochemical impedance spectroscopy methods over a pe-riod of several months. A multi-solution protocol was used to study the influence of the ionic strengthof the sample solution, ion charge, and mobility, and the sample pH values on the performance ofthe reference electrodes. The SSC reference electrodes were used in the calibration of commercialindicator 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 theSSC reference electrodes. The obtained results for the same samples were compared with the resultsgiven by an independent laboratory specialized in routine water analyses. The agreement betweenthe results was very good and even better than the case where commercial reference electrodes wereused. Our study showed that the SSC reference electrodes exhibit good long-term stability andexcellent performance, both in the calibrations and analyses of environmental samples.