Determination of Rare Earth Impurities in High-purity Lanthanum Oxide Using Electrothermal Vaporization/ICP-AES after HPLC Separation

Abstract

A new method for determination of trace rare earth impurities in high-purity La2O3 by HPLC combined with electrothermal vaporization inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES) is proposed. The chromatographic retention behaviors of matrix (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 use of EDTA as an eluent enables effective elution of rare earth impurities from a HPLC column. The influence of EDTA in ETV-ICP-AES was also discussed. The experimental results showed that a favorable separation between matrix (La) and rare earth impurities could be obtained within 30 min. The method proposed has been applied to the analysis of high-purity La2O3; the results obtained were in good agreement with those obtained by ICP-MS. Under the optimum conditions, the detection limits (DLs) for 14 rare earth elements (REEs) were in the range of 0.8 ng/ml (Yb) to 48 ng/ml (Ce). The recoveries of 14 REEs were in the range of 90% to 110%.

High‐Performance Liquid and Ion Chromatography: Separation and Quantification Analytical Techniques for Rare Earth Elements

“…We have compiled in Figure 6 LOD data from the chromatographic literature for the REEs to show graphically the characteristic odd-even pattern. In fact, our compilation of LOD values shows that, besides our work Verma, 2003, Santoyo et al 2006), this odd-even pattern is commonly observed by many other researchers as well ( Figure 6; viz., Kawabata et al 1991, Shuai et al 2000, Tsakanika et al 2004. In fact, our compilation of LOD values shows that, besides our work Verma, 2003, Santoyo et al 2006), this odd-even pattern is commonly observed by many other researchers as well ( Figure 6; viz., Kawabata et al 1991, Shuai et al 2000, Tsakanika et al 2004.…”

“…The capabilities of the ICP-AES system were helpful in quantifying these elements including Y. Shuai et al (2000) determined the REE impurities in RE oxides. Shuai et al (2000) determined the REE impurities in RE oxides.…”

The use of electrolyte redox potential to monitor the Ce(IV)/Ce(III) couple

“…This arrangement has been treated via classical flow reactor models such as the batch reactor (BR), the plug flow reactor (PFR) with recirculation, or the continuous stirred tank reactor (CSTR) with recirculation (Ford et al, 1992;Walker and Wragg, 1977). Previous studies to monitor the concentration of electrochemical active rare earth chemicals have normally involved discontinuous chemical analysis of reactants (or products) by atomic absorption spectroscopy (AAS) (Jain et al, 2001) and high-performance liquid chromatography (HPLC) (Shuai et al, 2000) which require relatively expensive instrumentation.…”

Analysis of high-purity solids by atomic emission spectroscopy and mass spectrometry with atom excitation and ionisation in inductively coupled plasma

“…36 The detection limits of the same order of magnitude were obtained with the use of thè Plasma Quad3' mass spectrometer for fifteen contaminants in cadmium separated from the matrix by sorption. 37 Chromatographic separation of impurities from the matrix has been used 14,15 in combination with ICP-AES and ETA for the analysis of lanthanum and cerium oxides.…”