Determination of rare earths in monazite sand and rare-earth impurities in high-purity rare-earth oxides by high-performance liquid chromatography

Abstract

Using high-performance liquid chromatography it has been possible to separate 14 lanthanide elements in less than 40 min by elution with an ahydroxyisobutyric acid concentration gradient. LiChrosorb KAT cation exchanger (10 pm) is used as the packing material and the eluted lanthanides are detected with an ultraviolet detector after complexation with Arsenazo 111. The detection limit is about 0.1 pg.Determinations of the rare-earth composition in monazite sand and .rareearth impurities in high-purity lanthanum(III), cerium(IV), samarium(II1) and yttrium(II1) oxides were carried out. The proposed method is more convenient than others, and the separation of major components is not necessary in analyses of high-purity rare earths; the elution time is only about 1 h.

Rapid, high-purity, lanthanide separations using HPLC

“…2). Ranges for both variables were chosen to encompass the conditions of previous works cited from the literature [2][3][4][6][7][8][9][10][11][12][13][14]. Separation resolutions were calculated from peak RTs and widths reported directly from the Chormeleon software package provided by Dionex.…”

“…Several publications report the use of HPLC/cation exchange resin/␣-HIB eluent to effectively separate the lanthanide group of elements [4,[6][7][8][9][10][11][12][13][14]. In general terms, there will be a particular concentration and pH of the eluent that is best suited for separating a particular pair of neighboring peaks.…”

“…The published average SRs for HPLC methods utilizing ␣-HIB and a cation exchange column range from 1.5 to 2.4 [4,[6][7][8][9][10][11][12][13][14]. While a SR of 1.5 or greater theoretically represents less than 1% cross-contamination between two Gaussian peaks [15], this level of separation was not reached for each of the neighboring Lns in practice since these reported SRs represent average values from a set of numbers with significant variability and in many cases from chromatograms that exhibited significant peak tailing (i.e., not characterized as Gaussian peaks).…”

“…Both ion and reverse-phase chromatography methods were originally applied using gravity fed columns. Today, such methods are often performed under pressure or vacuum, allowing the use of smaller diameter columns and resins that in turn provide a greater number of theoretical plates and therefore enhance overall separation [6][7][8][9][10][11][12][13][14]. However, there are physical limitations of pressurized systems based upon the nature of the resin being used.…”

Quantification of trace amounts of rare earth elements in high purity gadolinium oxide by sector field inductively coupled plasma mass spectrometry (ICP-MS)

“…It can also be used in optical glass manufacturing and in the electronic industry. Several analytical techniques have been used for the quantification of rare earth element (REE) as impurities in high purity materials [1][2][3][4][5][6]. Stijfhoorn et al [7] and Zang et al [9] evaluated the spectral interference of REEs in high purity europium, yttrium, and scandium oxide analyzed by inductively coupled plasma mass spectrometry (ICP-MS).…”