“…In such sensors, the electrode surface is covered with a sensing material that facilitates the charge-transfer reactions between the electrode and the solution (Barroso, Santos-Alvarez, Delerue-Matos, & Oliveira, 2011;Durst, Baumner, Murray, Buck, & Andrieux, 1997;Ziyatdinova, Kozlova, & Budnikov, 2016). Many sensing materials have been used as chemical modifiers, for instance, carbon nanotubes, graphene, nanoparticles, porphyrins, phthalocyanines or conducting polymers among others (García-Hernández, García-Cabezón, Martín-Pedrosa, de Saja, & Rodríguez-Méndez, 2016).…”