Methods for separation of trace amounts of platinum and investigation of the influence of interfering elements during platinum determination in copper ores and copper concentrates by graphite furnace atomic absorption spectrometry

A THGA graphite furnace with Zeeman background correction has been used to determine platinum content in copper ore and copper concentrate at the part per billion (ppb) concentration level. Two different procedures for the separation of trace platinum have been applied: (i) use of an ion exchange resin; and (ii) a two-stage method based on platinum separation on inorganic carriers. The influence of interfering elements in the matrix (Cu, Pb, Fe, Ti, V, Au, Pd, Ir, Rh and AI) has been examined using a graphite furnace. It was found that the presence of Cu (12.5-100 mg l(-1)), Pb (100-500 mg l(-1)), Fe (100-2000 mg l(-1)), Ti (25-100 mg l(-1)), V (25-100 mg l(-1)), Au (25-300 mg l(-1)), Pd (20-250 mg l(-1)), Ir (0.5-3.5 mg l(-1)) and Rh (0.025-1 mg l(-1)) in the samples analyzed has no effect on the platinum absorption signal when using a recommended temperature program (T-pyr = 1300 C, T-at = 2450degreesC). Spectral interference was observed, which was due to aluminum, as a result of the close neighborhood of the Pt 265.945-nm and Al 266.039-nm lines. This interference could not be eliminated by the Zeeman background correction. (C) 2001 Elsevier Science B.V. All rights reserved.