Applicability of Capillary Electrophoresis to the Analysis of Trace Rare Earth Elements in Geological Samples

Abstract

This study developed a methodology to analyze trace rare earth elements (REEs) in geological materials by capillary electrophoresis (CE). Changed from dilute HNO3 into a water medium by heating, REE ions are detectable at approximately 2 ng mL(-1). In the presence of coexisting elements from geological samples, REE separations were carried out. After sample fusion with Na2O2 and interference separation with ammonium pyrrolidinedithiocarbamate chelate, REE analytes were coprecipitated with Mg(OH)2 at pH 8.5, and then prepared into a water medium for CE determination. Using the standard addition method, this protocol was validated by analyses with better than 5% precision. This method was applied to geological materials; the REE results are in consistence with their certified values. With electrokinetic injection, internal standard (IS) selected among lanthanides is a prerequisite of high-quality REE data. An approach was proposed to derive the IS content for further correcting its contribution from unknown samples.

An efficient method for the separation of REEs from Ba for the accurate determination of REE content in Ba-rich samples by ICP-MS

“…In addition, the standard addition method, which is commonly used to monitor the recovery of REEs in unknown samples, was used to evaluate the recovery of REEs in these reference materials. 47,48 The method was implemented, first, by preparing two identical samples, one of which was added with known quantities of REEs, and then the two samples were analyzed using the same analytical steps at the same time. Finally, the recovery (%) of REEs was calculated as the ratio of the difference between the result obtained after adding quantitative REEs and the result obtained by not adding REEs to the initial quantitative REE values.…”

Simultaneous determination of rare earth elements in ore and anti-corrosion coating samples using a portable capillary electrophoresis instrument with contactless conductivity detection

“…Note that the employment of acetic acid in the BGE serves not only for pH adjustment but also for complexation of the REEs. The presence of acetate ligand helps to improve the separation of the REEs, especially between Eu and Gd [20,21]. The good separation achieved for the REEs in this case is due to the concurrent complexing effects of the HIB − and acetate ligands.…”

“…Reviews on applications of CE for metal species determination in environmental and biological samples can be found in [11][12][13][14][15]. Indeed, the simplest format of the technique, namely capillary zone electrophoresis (CZE) has been reported for the determination of REEs in different matrices, using UV-vis (UV-vis) detection [16][17][18][19][20][21][22][23], laser induced fluorescence (LIF) detection [24,25], mass-spectrometric detection [26] or detection by ICP-MS [27,28]. Other modes of CE have also been used for this purpose, notably micellar electrokinetic chromatography (MEKC) [29][30][31], electrokinetic supercharging (ESK) [32] and isotachophoresis (ITP) [33].…”

A label-free conjugated polymer-based fluorescence assay for the determination of adenosine triphosphate and alkaline phosphatase

“…We can utilize triethanolamine as a suitable masking reagent in the real samples containing Fe 3+ . 34 Then we investigated the relationship between the PL intensity of PPESO 3 and Cu 2+ concentration and the results were shown in Fig. 2.…”