Electrochemical Determination of Copper (II) Based on Three-Dimensional L-Cysteine Monolayer Assembled on Gold Nanoparticles

Copper (II) determination with a three-dimensional monolayer modified electrode prepared by assembling L-cysteine on gold nanoparticles (L-cys/GNP/GCE) was studied in this paper. With the presence of gold nanoparticles, three-dimensional L-cysteine monolayer-modified electrode showed better voltammetric response for copper (II) than traditional two-dimensional L-cysteine assembled on planar electrode by increasing the response current and decreasing the peak separation of redox waves. Furthermore, the influences of pH and pre-concentration time on the voltammetric behavior of copper (II) at L-cys/GNP/GCE were investigated. By cyclic voltammetry, the three-dimensional monolayer-based electrochemical sensor presented a wide linear response range between 1times10^-6 g/L and 5times10^-4 g/L for copper (II) determination with only 2 min pre-concentration. The good anti-interference and stability of modified electrode in copper (II) determination were also observed.