Electrochemical determination of trace copper(ii) based on l-cysteine functionalized gold nanoparticle/CdS nanosphere hybrid

Abstract

This paper describes a simple and efficient electrochemical assay for the determination of trace Cu(II) employing L-cysteine functionalized gold nanoparticles/CdS nanospheres/glassy carbon electrode (L-cys/AuNPs/CdS/GCE) as an enhanced sensing platform. The prepared sensor exhibited a high active surface area, excellent electron transfer properties, and greatly enhanced sensitivity for Cu(II) in comparison with AuNPs/CdS/GCE, L-cys/AuNPs/GCE and CdS/GCE, due to the synergistic effect of L-cysteine, Au nanoparticles and CdS nanospheres. The experimental conditions, namely preconcentration time, electrolyte and pH value, were optimized in order to maximize the sensitivity of the measurements. Under optimal conditions, the SWASV stripping signals for Cu(II) were linear in the concentration range of 0.5 to 200.0 nmol L⁻¹, and a detection limit of 0.1 nmol L⁻¹ (S/N = 3) was obtained. The prepared sensor also exhibited excellent repeatability and selectivity for Cu(II) over competing environmentally relevant metal ions. It was further applied to determine Cu(II) in real water samples, and the results agreed satisfactorily with the certified values.