Cyclic Voltammetric Determination of Mercury with Calix4arene Modified Glassy Carbon Electrode

The modified electrode was prepared by electrodeposition of a film of calix4arene on the surface of glassy carbon electrode (GCE) through scanning over the potential range from -0.2 to -0.8 V (vs. Ag/AgCl) from a solution of 1.0×10-3mol·L-1 calix4arene dissolved in 0.1 mol·L-1 tetrabutyl ammonium perchlorate. The surface property of the calix4arene modified GCE were studied by AC impedance method and atomic force microscopy (AFM), and its electrochemical property studied by cyclic voltammetry. It was found that the calix4arene modified GCE showed a remarkable oxidation peak of Hg at the potential of 0.28 V (vs. Ag/AgCl). Under the optimized experimental conditions, linear relationship between values of oxidation peak current and concentration of mercury(Ⅱ) was obtained in the range of 2.0×10-6-1.7×10-3mol·L-1, with its detection limit (3S/N) of 5.0×10-7mol·L-1. The proposed method was used in the analysis of a simulated water sample, the results ontained were in conformity with those found by FAAS.