Novel sensor for simultaneous determination of K+ and Na+ using Prussian blue pencil graphite electrode

A novel approach for simultaneous determination of K+ and Na+ based on Na+-inhibited and direct K+ intercalation processes at Prussian blue is proposed. The competing processes of Na+-inhibited and direct K+ intercalation were established for the first time using a Prussian blue pencil graphite electrode (PB-PGE) and manipulation of the cyclic voltammetry (CV) scan rate. The pair of cathodic peak potentials result of Na+-inhibited and direct K+ intercalations was used as analytical signals for K+ and Na+ determination via a simultaneous standard addition method. Simultaneous determination of K+ and Na+ was demonstrated in a laboratory prepared sample with satisfactory results, suggesting the proposed approach is amenable for further development as a Prussian blue-based electrochemical method for simultaneous K+ and Na+ determination.