Ion-exchange chromatography with an oxalic acid-α-hydroxyisobutyric acid eluent for the separation and quantitation of rare-earth elements in monazite and xenotime

Abstract

Key WordsColumn liquid chromatography Ion-exchange Rare-earth elements Monazite Xenotime SummaryAn oxalic acid-c~-hydroxyisobutyric acid eluent has been used for the separation and determination of rareearth elements by high-performance ion-exchange chromatography. Fifteen rare-earth elements were separated within less than 25 rain on a 150 • 4.6 mm i.d. column packed with 5-1am sulfonic acid-bonded silica particles by elution with a combined gradient of 0.60-9.0 mM oxalic acid and 19.0-5.0 mM ot-hydroxyisobutyric acid at pH 4.6. Detection and quantitation of the separated rare-earth elements was accomplished by visibleabsorbance measurement at 600 nm after postcolumn reaction with arsenazo I. The gradient of the two complexing agents was optimized to enable the separation of yttrium(III) without interference from other elements, especially dysprosium(III) and terbium(III). Mass detection limits of the elements were in the range of 2-4 ng. Finally, the chromatographic system was applied to the quantitative analysis of rare-earth elements in monazite and xenotime.

Separation and direct detection of heavy lanthanides using new ion-exchange chromatography: fast Fourier transform continuous cyclic voltammetry system

“…Fernández and Alonso [20] recently used ethylenediaminetetraacetic acid (EDTA) as a mobile phase in the separation of lanthanides. A mixed gradient of two eluents has also been used in some researches [13,21]. The most popular eluting agent in these works is HIBA due to a good degree of separation among adjacent lanthanides.…”

Development of an analytical method for accurate and precise determination of rare earth element concentrations in geological materials using an MC-ICP-MS and group separation

“…A 2 M stock solution of HIBA was adjusted to pH 4.6 using ultrapure NH 4 OH (Merck). Nuryono et al (1998) showed that the elution time and resolution during HIBA column chromatography depended on the pH of HIBA. Therefore, the authors recommended that pH 4.6 is optimal for REE separation by HIBA column chromatography because at pH < 4.6, the eluent is too weak to elute REE ions and at pH > 4.6, the resolution is too low to guarantee adequate REE separation.…”