Graphite furnace atomic absorption spectrometric (GFAAS) determination of Cu, Cd, Cr, Mn, Ni and Pb in tellurium metal using precipitation and ion-exchange procedures

Abstract

 Two independent procedures have been developed for the determination of Cd, Cu, Ni, Mn, Cr and Pb in high-purity tellurium by GFAAS. In the first, tellurium is precipitated as TeO₂ in the presence of EDTA at pH 4.5±0.2 to remove of 99.4% of tellurium as tellurium dioxide. The supernatant is analysed for impurities. In the second procedure, the trace impurities are preconcentrated on a Chelex-100 resin column at pH 9.4±0.2, and eluted by two column volumes of 2 mol/L HNO₃. In this case a matrix separation coefficient (k_s) of 1500 is achieved. The analyses are carried out by GFAAS. The relative standard deviations of the analyte concentrations in the samples are 4–8%. Separation of the matrix and recovery of the analytes are essentially complete as confirmed by standard addition of the analytes to the matrix.