Application of square-wave voltammetry to the determination of heavy metals in thorium compounds without prior matrix separation

An analytical procedure for determination of the Cd, Pb, Cu, Sb, Zn and Cr is described in thorium compounds such as thorium oxide and thorium nitrate without prior matrix separation. Square wave voltammetry is employed using a HMDE/Ag-AgCl (3M KCl)/Pt-rod electrode system. Determination of the Cd, Pb, Cu and Sb is carried out simultaneously using 2M HCl as supporting electrolyte. For determination of Zn, 0.1M HCl is used and for Cr a mixture of 0.01 M acetate buffer, 0.5M sodium nitrate and 0.04M diethyl triamine pentaacetic acid (DTPA) (complexing agent) are used as supporting electrolyte. This method is suitable for determination of Cd, Pb, Cu, Sb, Zn and Cr as low as 0.05 μg/g, 0.2 μg/g, 0.1 μg/g, 0.2 μg/g and 0.05 μg/g respectively with a relative standard deviation of 10-12%. (author)