The determination of trace amounts of refractory metal elements (Ti, V, Zr, Nb, Mo and Ta) in high-purity iron by inductively coupled plasma mass spectrometry (ICP-MS) was examined. We examined a separating technique involving trace amounts of refractory metal elements from a high-purity iron matrix using the cupferron coprecipitation separation method and the measurement conditions of ICP-MS. Using the established analysis method, after 150 cm
3 of hydrochloric acid (1 + 4) was added to 1 g of high-purity iron sample, they were decomposed on a 453 K hot plate. After the sample solutions were cooled at room temperature, an ascorbic acid solution and cupferron solutions were added to 10 cm
3 portions, and then filtered. The paper filter and sediment were then added to 10 cm
3 of nitric acid and 10 cm
3 of perchloric acid, and dried through evaporation. After 150 cm
3 of hydrochloric acid (1 + 4) was added to salt, it was dissolved; this operation was then repeated again. After 2 cm
3 of nitric acid was added to this salt and it was dissolved, it was dried through evaporation. After the process of evaporation to dryness was performed 3 times, nitric acid (1 + 100) was added to the salt and dissolved. The sample solution was measured by ICP-MS. The concentration of the iron matrix in sample solution was decreased to about 200 μg cm
−3, and it didn’t change. The background signal at mass 90 was decreased by nitric acid-treatment process, which enabled this difficult experiment to be carried out. The recovery rates of 6 added elements were 99% for Ti, 95% for V, 98% for Zr, 98% for Nb, 96% for Mo and 96% for Ta, respectively. The detection limits were 0.08 ng cm
−3 for Ti, 0.009 ng cm
−3 for V, 0.01 ng cm
−3 for Zr, 0.008 ng cm
−3 for Nb, 0.01 ng cm
−3 for Mo and 0.004 ng cm
−3 for Ta, respectively.
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