PRECONCENTRATION METHODS FOR DETERMINATION OF TRACE AMOUNTS OF IMPURITIES IN HIGH-PURITY COPPER-SALTS BY ATOMIC-ABSORPTION SPECTROMETRY AND INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

Various extraction systems including hydrochloric acid-long chain quaternary ammonium salts-isobutyl methyl ketone were applied for the investigation of the possibility of the extractive separation and concentration of trace amounts of Ag, Bi, Cd, Fe, Mo, Pb, Sb and Zn from high-purity CuSO4, CuCl2, Cu(CH3CO2)2, CuCO3 and Cu(NO3)2. Preconcentration of the trace components Al, Ag, Ba, Bi, Ca, Cd, Co, Cr, Fe, Mn, Ni, Pb, and Zn from the copper salts was achieved by precipitation of the matrix as CuCl with ascorbic acid. The advantages and disadvantages of both the extraction and precipitation preconcentration procedures are discussed. The best results for multi-element preconcentration were obtained with the extraction system hydrochloric acid-2% methyltrioctylammonium chloride-isobutyl methyl ketone. The extraction procedure permits the flame atomic absorption spectrometric (AAS) determination of 5 x 10(-6)% Ag, Cd and Zn, 1 x 10(-5)% Bi and Fe and 5 x 10(-5)% Mo and Sb in high-purity copper salts. When the extraction is combined with electrothermal AAS, the determination of Ag, Bi and Cd is possible up to 1 X 10(-8)%, of Fe up to 1 X 10(-6)% and of Sb up to 5 x 10(-7)%. The precipitation procedure permits the determination of 1 X 10(-5)% Ba, Ca and Mn, 2 x 10(-5)% Ag, Cd and Zn, 5 x 10(-5)% Al, Co, Cr, Fe and Ni and 1 x 10(-4)% Pb using inductively coupled plasma atomic emission spectrometry.