Determination of Trace Amounts of Antimony and Boron in High-Purity Iron and Steel by Isotope Dilution/Inductively Coupled Plasma Mass Spectrometry

摘要

The highly sensitive and precise determination method for trace amounts of Sb and B in high-purity iron and steel has been established by the isotope dilution/Inductively coupled plasma mass spectrometry. For the determination of Sb, the iron matrix was separated by anion-exchange chromatography using Dowex I-X8 in hydrofluoric acid solution, and the isotope ratio (~121Sb/~123Sb) of the HNO_3/H_2O_2 eluate was measured by ICP-MS. The isobaric interference of ~123Te was corrected by subtracting the intensity of ~123Te obtained by the relative intensity of ~123Te and ~125Te. For the determination of B, after the treatment of sulfuric acid-phosphoric acid fuming for the complete decomposition of boron nitride, B was separated by the anion-exchange chromatography using Amberlite IRA-743 at pH 8. The CyDTA was added to prevent the hydrolysis of iron. The isotope ratio (~11B/~10B) of the HCl eluate was measured by ICP-MS. By these methods, Sb and B in the range of mu g/g could be determined with good precision. The limit of detection is 5.8 ng/g for Sb and 16 ng/g for B in steel.