DETERMINATION OF TRACE NON RARE-EARTH ELEMENTS IN HIGH-PURITY RARE-EARTH-OXIDES BY ICP-AES WITH MICROCOLUMN PRECONCENTRATION IN A FLOW-INJECTION SYSTEM

A new-method for the determination of trace non-rare earth elements in high purity rare earth oxides by ICP-AES with preconcentration on an active carbon-silica gel microcolumn in a flow injection system is described in this paper. Experimental parameters such as pH, flow rate, reagent concentration, length of reaction coil, eluent acidity, etc. were optimized. In the buffer solution of NH3 . H2O/NH4Cl at pH 4.6, Al, Cr, Cu, Fe, Pb, V and Zn can be preconcentrated and then eluted with 4.5 mol/L nitric acid utilizing stop-flow technique. The enrichment factors were in range of 8.1 similar to 12.6 With detection limits of mu g/mL level, and the RSD with metals at mu g/g level were 2.3 similar to 5.0% (n = 7). The method proposed can reduce the matrix interference effectively, and has been applied to the determination of non-rare earth metals at mu g/g level in high purity Eu2O3 With satisfactory results.