Determination of Trace Cadmium in Water by Anodic-Stripping Voltammetry Using Dithizone-Modified Glassy Carbon Electrode / 环境与健康杂志

ABSTRACT

Objective To establish an anodic-stripping voltammetry method for determination of trace cadmium in water using dithizone-modified glassy carbon electrode. Methods Cd2+ was preconcentrated on the surface of the dithizone-modified glassy carbon electrode at -1.21 V, and subsequently reduced to Cd on the electrode. When the electric potential of electrode increased from -1.21 V to -0.30 V, the reduced cadmium was oxidized and stripped from surface of electrode, and the sensitive anodic-stripping peak was observed at -0.79 V. The parameters including the selection of supporting electrolytes, pH value, the amount of dithizone, concentration electric potential and time were optimized. Results The most suitable reaction medium was 0.1 mol/L NaAc-Hac-KI solution at pH value of 3.00.The most suitable volume of 1g/L methenyl chloride-dithizone solution was 10 ?l. The optimized concentration electric potential and time were -1.21 V and 5 min respectively. The linear range of this method was 5?10-8-2?10-6 mol/L. The average recovery rate was 98.42%. The relative standard deviation was 2.90%(n=8). The detection limit was 6?10-9 mol/L. Conclusion The method was simple ,rapid and sensitive,which was suitable for the determination of trace cadmium in practical water sample.