Functionalized graphene oxide-based carbon paste electrode for potentiometric detection of copper ion(ii)

Abstract

For the first time, a novel copper ion(II) carbon paste electrode (CPE) based on high-density carboxyl functionalized graphene oxide (GO) is reported. A new hybrid material, 2-amino-5-mercapto-1,3,4-thiiodiazole grafted onto nanoscale graphene oxide (AMT-g-NGO), was introduced as a neutral carrier. The electrode exhibits an excellent Nernstian response to copper ion(II) ranging from 1.0 × 10⁻⁷ M to 1.0 × 10⁻¹ M with a slope of 26.2 mV dec⁻¹. Meanwhile, the proposed electrode shows fairly good selectivity and a long life time (2 months). Moreover, the excellent performance on low detection limit (4.0 × 10⁻⁸ M), wide applicable pH range (3.0–7.0) and fast response time (15 s), reveal the superiority of the electrode. The response mechanism of the electrode was investigated using AC impedance technique and UV-vis spectroscopy. The sensor can be used as indicator electrode for potentiometric titration of Cu²⁺ ion with EDTA and successfully applied to the determination of Cu²⁺ ion in different real samples.