Conjugates of graphene oxide covalently linked ligands and gold nanoparticles to construct silver ion graphene paste electrode

We reported on the synthesis and application of ionophore–gold nanoparticle conjugates in Ag+ graphene paste electrode. Ionophore was a novel graphene oxide nanosheets (NGO) covalently grafted 2-thiophenecarboxylic (TPC) hybrid material. The hybrid material NGO–TPC decorated with gold nanoparticles was used as both a receptor and an ion-to-electron transducer to fabricate Ag+ graphene paste electrode. The developed electrode was highly selective to Ag+ over other tested cations and exhibited an excellent Nernstian slope of 59.3 mV dec−1 ranging from 8.4×10−7 to 1.0×10− M with a detection limit of 6.3×10−7 M. Moreover, it also showed a fast response time and a long lifetime. Importantly, the new method of immobilizing ligands on NGO nanosheets to construct electrode successfully solved the universal problem of the electrode components loss from ion-selective electrode.