Electrochemical Complexation Studies of Cadmium (II) for its Ultra Trace Determination

A selective and sensitive method for determination of cadmium by differential pulse polarography is presented. The method is based on complexation of Cd(II) ions with citric acid in potassium nitrate medium, followed by electrochemical reduction of Cd(II)-complex by DPP. Optimal conditions were obtained at citric acid concentration of 0.1 M, reduction potential of 0.56V (vs SCE) and scan rate of 12mV/sec. Under optimized conditions linear calibration curves were established for the concentration of Cd(II) in the range of 0.008-30 µg/ml, with the detection limit of 0.008 ppm. The method was successfully applied to the ultra trace determination of Cd(II) in waste waters from industries. Interferences were also evaluated.