SYSTEMATIC INVESTIGATIONS OF THE MULTIELEMENT PRECONCENTRATION FROM COPPER BY PRECIPITATION OF THE MATRIX AS COPPER(I) OXIDE AND COPPER(I) THIOCYANATE

Two methods for multi-element preconcentration from copper by reductive matrix precipitation are presented. In systematic investigations on the coprecipitation behaviour of Ag, Al, Au, Bi, Cd, Co, Cr, Fe, Ga, In, Mn, Mo, Ni, Pb, Sb, Se, Sn, Te and Zn during precipitation of the copper matrix as Cu2O or CuSCN, the separation parameters were optimized. By combination with a hexamethyleneammonium hexamethylenedithiocarbamate collector precipitation, a concentration of 8 elements (Cu2O precipitation) or 13 elements (CuSCN precipitation) in a small volume was achieved. The limits of detection of the procedures are, depending on the element, 0.1-5-mu-g g-1 for flame atomic absorption spectrometry (AAS) and 0.01-0.1-mu-g g-1 for graphite furnace AAS. The relative standard deviations are about 3%. The analytical performance of the procedures is compared with that of an electrolytic copper separation.