Determination of Trace Cu(Ⅱ) by Cyclic Voltammetry Using Histidine/Graphene Modified Glassy Carbon Electrode

The surface of a glassy carbon electrode was modified successively with grapheme and histidine by drop-coating method and electrochemical method. The modified glassy carbon electrodes was used to measure Cu(Ⅱ) by cyclic voltammetry. The oxidation peak current of Cu(Ⅱ) on the modified electrode increased significantly in comparison with bare glassy carbon electrode, because of the better electrical conductivity of graphene and the coordination adsorption effect of histidine. Under optimized conditions, the linear relationship between oxidation peak current and the concentration of Cu(Ⅱ) was in the range of 2.30×10-8-3.06×10-5mol·L-1, with a limit of quantification (10S/N) of 1.5×10-9mol·L-1. The method was used to measure samples, giving recovery rates by standard addition method in the range of 94.0%-102% and RSD (n=10) of 2%. The result obtained by this method was consistent with that of atomic absorption spectrometry.