The influence of an intermediate layer on the composition stability of a polymeric ion-selective membrane

This paper focuses on the influence of the different materials used as an intermediate layer between ionophore doped polymeric membranes and metallic conductors on ion-selective membranes composition stability. The quantitative determination of the membranes components loss from of solid contact ion-selective electrodes (SC-ISEs) during contact with aqueous solutions was performed by stripping voltammetry. A correlation between the leaching of the lipophilic salt rate and the presence of carbon black and a conducting polymer with different dopants layers is observed. The sodium selective SC-ISEs with Printex U carbon black presented in this paper for the first time showed the theoretical potentiometric response (59.11 mV/pNa) and a very good long-term potential stability (16.4 μV h−1).

► The stability of the membrane composition depends on the conducting layer used.
► The leaching of the lipophilic salt rate was studied.
► The sodium selective SC-ISEs with Printex U showed the theoretical potentiometric response and a very good long-term potential stability.
► The sodium tertraphenylborate leached out from sodium-sensitive membranes of SC-ISEs was determined by DP CSV.