A graphene/ionic liquid modified selenium-doped carbon paste electrode for determination of copper and antimony

Abstract

A graphene (GN) and ionic liquid (IL) modified selenium-doped carbon paste electrode (GN/IL/Se/CPE) was established to simultaneously determine trace Cu(II) and Sb(III) by differential pulse voltammetry (DPV). Several parameters which affect the stripping current response were investigated and optimized, including the proportion of Se powder, concentration of hydrochloric acid, deposition time and deposition potential. The DPV curves were recorded by simultaneous deposition of Cu(II) and Sb(III) at −0.4 V for 50 s in a supporting electrolyte solution HCl of 0.30 mol L⁻¹. Under the optimized conditions, the GN/IL/Se/CPE sensor has a good linear response in the range of 2.0 × 10⁻⁶ to 7.0 × 10⁻⁵ mol L⁻¹ for Cu(II) and 2.0 × 10⁻⁶ to 4.0 × 10⁻⁵ mol L⁻¹ for Sb(III). The detection limits were 6.6 × 10⁻⁷ mol L⁻¹ for Cu(II) and 4.3 × 10⁻⁷ mol L⁻¹ for Sb(III). The sensor showed favorable stability and higher sensitivity. The present work extends the scope of these devices as mercury-free sensors and can be used to detect Cu(II) and Sb(III) simultaneously.