Reduced graphene oxide in the construction of solid-state bromide-selective electrode

To improve the electrochemical performance of solid-state printed electrodes, reduced graphene oxide is used as an intermediate layer (mediator) between the surface layer of a current collector and the ionophore layer. A graphene oxide film was deposited onto the surface of printed electrodes by drop-casting, followed by reduction and electrochemical deposition. An ionic liquid 1,3-dihexadecylimidazolium bromide served as ionophore. The effect of reduced graphene oxide on the characteristics of the ion-selective electrode is studied, and it is shown that the sensors electrochemically modified with reduced graphene oxide have the best performance. These sensors exhibit a stable, well-reproducible response to bromide ions with the slope of the electrode function close to the Nernstian value (−60.7 ± 0.7 mV/dec) and a low detection limit of 3.6 × 10−6 M. The response time for all of the electrodes does not exceed 15 s even in dilute solutions.