Study on electrochemical behavior of cadmium on inlaid carbon nanotubes-bismuth film glassy carbon electrode and determination by potentiometric stripping method

A novel inlaid carbon nanotubes-bismuth film glassy carbon electrode was prepared. The electrochemical behavior of Cd on the electrode was investigated by cyclic voltammetry. An inreversible oxidation peak of Cd on the electrode was observed, Epa=0.637 V（vs．SCE）. High sensitive electrochemical response of Cd on this electrode was obtained. The influencing factors for differential potentiometric stripping analysis of Cd were tested. The optimum conditions were -1.1 V of deposition potential, 0.4 mg/L of Bi3+ concentration, pH 4.6 HAc-NaAc buffer solution. The analytical reliability of this electrode was enhanced by in-situ plated bismuth film and standard addition method. The stripping peak height (dt/dE) is a linear function of Cd concentration over the range 0.1-2.0 μg/L in the optimum conditions, with the detection limit of 0.2 μg/L.The proposed method was application in the determination of Cd in practical samples, the result was in agreement with those provided by AAS, RSD and the recovery were 3.1%-7.2%, 92%-102%, respectively.