Three calibration techniques combined with sample-effective design of experiment based on Latin hypercube sampling for direct detection of lanthanides in REE-rich ores using TXRF and WDXRF

Abstract

This study concerns the simultaneous detection of five rare-earth elements (REEs) – Ce, La, Nd, Pr, Sm – in ores and nodules using two X-ray fluorescence techniques (XRF): total reflection...

Direct determination of lanthanides by LIBS in REE-rich ores: comparison between univariate and DoE based multivariate calibrations with respect to spectral resolution

“…Latin hypercube sampling (LHS), first proposed by McKay et al , 50 is superior to all abovementioned DoEs as it can be constructed with low correlation for a large number of factors 51 and a tunable number of levels. In our resent study, 52 the DoE based on LHS (20 levels and 5 factors) with an extremely low correlation (<0.03) enabled the construction of robust PLS-R and principal component regression (PCR) calibration models using artificial mixtures of REE compounds (Fe and Ti oxides as a matrix) that outperformed univariate models providing up to several times better accuracy of Ce, La, Nd, Pr and Sm determination in REE-rich ores and ferromanganese nodules by TXRF and WDXRF.…”

Application of Total-Reflection X-Ray Fluorescence Spectrometry (Txrf) to Geological Objects: Experience of the TXRF Laboratory, Center for Geodynamics and Geochronology

“…TXRF can be applied for direct analysis of iron, manganese, ferromanganese, nickel-copper sulfide ores, oceanic and lacustrine nodules [Pashkova et al, 2020;Akhmetzhanov et al, 2021;Chubarov et al, 2021]. The suspension preparation (5 mL of 1 % Triton X-100 solution and 20 mg of fine powder with a size <10 μm and internal standard of Ga) gives a possibility for fast reliable determination of major and minor elements by the internal standard method with the recovery values 75-125 %.…”

“…For instance, the differences between the TXRF results and the certified values in CRMs may be more than 30 % for As, Pb, V, Cr, Ba in the nodules due to PbLα/AsKα, BaLα/TiKα, CrKα/VKβ, VKα/TiKβ lines overlapping [Pashkova et al, 2020;Chubarov et al, 2021]. Chemometric approaches may be used to solve this problem [Akhmetzhanov et al, 2021]. It was shown that the calibration models based on partial least squares and principal component regressions provide a quantitative determination of Ce, La, and Nd content in ores and nodules using the TXRF method.…”

Atomic spectrometry update – a review of advances in X-ray fluorescence spectrometry and its special applications

“…In a related study, similar improvements were obtained 57 by wet milling a clay CRM to reduce particle sizes even further (to 1–2 μm). Akhmetzhanov et al 58 compared multi- and univariate calibration for both TXRF and WDXRF analyses for the determination of REE in ores with the aim of assessing whether the cost-efficient suspension-assisted TXRF procedure could be used as an alternative to the WDXRF procedure which employed pressed pellets. A set of calibration samples with variable concentrations of REE was used to improve the accuracy.…”