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A new method for determination of trace iron in superconductor powder by ICP-AES was proposed. The instrument parameters were optimized, and the matrix effects as well as the method of eliminating interferences were also studied systemically. The results showed that matrix interference was serious when the amount of matrix increased, and the repeatability was poor, so it was necessary that separation and preconcentration were used to improve the accuracy and precision. In the experiment, complex was formed with Fe and phenanthroline after the matrix elements Bi and Cu were masked by triethanolamine in an appropriate acidity condition. Then the complex was quantitatively adsorbed by activated carbon, and desorbed by 1 : 1 HNO3. The enrichment conditions were investigated in detail. Under the optimal condition, an artificial sample was analysed, and the result was identical with reference values, with the RSD and detection limit being 2.42% and 0.033 microg x g(-1), respectively. The method was applied for the determination of trace iron in Bi-based superconductor powder samples with satisfactory results, in which the recoveries experiment was performed with the recovery coefficient falling in the range of 95.6% to 98.0%.

A new method for the determination of trace nickel in superconductor powder by ICP-AES was proposed. The instrument parameters were optimized, and the matrix effects as well as the method of eliminating interferences were also studied systemically. The results showed that matrix interference in the superconductor powder was serious when the amount of matrix increased, and the repeatability as well as the accuracy was poor, so it was necessary to used separation and preconcentration to improve the accuracy and precision. In this experiment, Ni-diacetyl dioxime complexes were enriched by toluene extraction in alkaline condition after eliminating the interference of major element Bi and partial Pb, Sr, Ca and Cu by eluting with anion exchange resin, then the Ni-complexes were back extracted by diluted hydrochloric acid. The enrichment conditions were investigated in detail and the recovery rate of Ni was higher than 95%. Under the optimal condition, an artificial sample was analysed, the result showed that the found values were identical with reference values, and the RSD and detection limit were 1.9% and 0.19 microg x g(-1), respectively. The method has been applied to the determination of trace nickel in Bi-based superconductor powder samples with satisfactory results.