Analytical Sciences


Abstract − Analytical Sciences, 20(6), 921 (2004).

Cyanex 923 as the Extractant in a Rare Earth Element Impurity Analysis of High-Purity Cerium Oxide
Taicheng DUAN,* Hongfei LI,** JianZhen KANG,* and Hangting CHEN*
*State Key Laboratory of Electroanalytical Chemistry, National Research Center of Electroanalytical and Spectroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 13002, China
**Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
In this work, the feasibility of employing Cyanex 923 as an extractant into the non-cerium REE (rare earth elements) impurity analysis of high-purity cerium oxide was investigated. Through investigations on the choice of the extraction medium, the optimium extraction acidity, matrix Ce4+ effect on the non-cerium REE ion extraction, the optimium extractant concentration and suitable extracting time, and oscillation strengh, it was found that when the phase ratio was at 1:1 and the acicidity was about 2% H2SO4, by gently shaking by hand for about 2 min, 10 mL of 30% Cyanex 923 could not extract even for a 20 ng amount of non-cerium REE3+ ions. However, the extraction efficiency for Ce4+ of 100 mg total amount under the same conditions was about 96%, indicating that a 25-fold preconcentration factor could be achieved. Thus, it was concluded that Cyanex 923 could be used in a REE impurity analysis of 99.9999% or so pure cerium oxide for primary sepapation to elimilate matrix-induced interferences encountered in an ICP-MS (inductively coupled plasma mass spectroscopy) determination.