HPLC Combined with ICP Spectrometry for the Determination of Trace Rare Earth Impurities in High-purity Rare Earth Oxides by Using 2-ethylhexyl Hydrogen 2-ethylhexylphosphonate Resin as the Stationary Phase

摘要

A new method is proposed to determine trace rare earth impurities in high-purity rare earth oxides by HPLC combined with inductively coupled plasma mass spectrometry (ICP-MS) or electrothermal vaporization inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES). The chromatographic retention behaviors of matrix (Ce and La) and rare earth impurities were studied using 2-ethylhexyl hydrogen 2-ethylhexylphosphonate (P507) resin as the stationary phase and dilute nitric acid as the mobile phase. It was found that the matrix (La or Ce) can be separated quantitatively with dilute nitric acid as mobile phase, and the use of EDTA as a eluent enable effective elution of rare earth impurities (Ce-Lu or Pr-Lu) from HPLC column. The experimental results showed that a favorable separation between matrix (La or Ce) and rare earth impurities (Ce-Lu or Pr-Lu) could be obtained within 60 min. The proposed method has been applied to the determination of 1 4 rare earth impurities in high-purity CeO_2 and La_2O_3 with satisfactory results,