Determination of trace rare earth impurities in high-purity cerium oxide by using electrothermal vaporization ICP-AES after HPLC separation with 2-ethylhexylhydrogen 2-ethylhexylphosphonate resin as the stationary phase

A method is proposed to determine trace rare earth impurities in high-purit y CeO2 by HPLC combined with electrothermal vaporization inductively couple d plasma atomic emission spectrometry (ETV-ICP-AES). The chromatographic re tention behaviours of the matrix (Ce) and rare earth impurities were studie d using 2-ethylhexyl hydrogen 2-ethylhexylphosphonate (P507) resin as the s tationary phase and dilute nitric acid as the mobile phase. It was found th at the matrix (Ce) can be separated quantitatively with dilute nitric acid as the mobile phase, and the rare earth impurities (Pr-Lu) can be eluted ef fectively by use of EDTA as an eluent. The experimental results show that a favorable separation between the matrix (Ce) and rare earth impurities (Pr -Lu) can be obtained within 60 min. The method proposed has been applied to determine 14 rare earth impurities in high-purity CeO2 with satisfactory r esults.