Electrochemical determination of copper (Ⅱ) based on three-dimensional L-cysteine monolayer assembled on gold nanoparticles

摘要

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, threedimensional 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 1×10-6 g/L and 5×10-4 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.