Simultaneous determination of trace amounts of cadmium, nickel and cobalt in water samples by adsorptive voltammetry using ammonium 2-amino-cyclopentene dithiocarboxylate as a chelating agent

This paper reports the use of an adsorptive voltammetric technique for the simultaneous detection of Cd(II). Ni(II) and Co(II) using ammonium 2-amino- cyclopente dithiocarboxylate as a selective complexing agent. Scans contain ing three resolved peaks corresponding to these metals were obtained in syn thetic and real samples. The reduction current peaks of the metals that wer e distinctly separated by 200 mV or more, allowing their determination over a wide range of concentrations. These metals can be quantified at concentr ations above 1.33 x 10(-8) mol dm(-3) Cd(II), 8.51 x 10(-9) mol dm(-3) Ni(I I) and 3.39 x 10(-10) mol dm(-3) Co(II). The influence of pH, ligand concen tration, scan rate, accumulations time and applied potential was investigat ed. The R.S.D. at a concentration level of 1.78 x 10(-7) mol dm(-3) Of Cd(I I), 3.40 x 10(-7) mol dm(-3) and Ni(II) and 1.7 x 10(-9) mol dm(-3) of Co(I I) was 2.5% for Cd(II), 2.7% for Ni(II) and 3.3% for Co(II). The method was applied to various water samples. (C) 2000 Elsevier Science B.V. All right s reserved.