|
ИСТИНА |
Войти в систему Регистрация |
ФНКЦ РР |
||
Direct determination of lanthanides by LIBS in REE-rich ores: comparison between univariate and DoE based multivariate calibrations with respect to spectral resolutionстатья Исследовательская статья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus- Авторы: Akhmetzhanov Timur F., Popov Andrey M.
- Журнал: Journal of Analytical Atomic Spectrometry
- Год издания: 2022
- Издательство: Royal Society of Chemistry
- Местоположение издательства: United Kingdom
- DOI: 10.1039/D2JA00188H
- Аннотация: Laser-induced breakdown spectroscopy (LIBS) was used to detect rare-earth elements (REEs) – Ce, La, Nd, Pr, Sm – in ores. The problems of significant overlapping of REE lines in LIBS emission spectra and high pairwise correlation between REE contents in certified reference materials (CRMs) of natural origin, decreasing the multivariate model prediction capacity are addressed in the study. The latter is done by employing a specially designed calibration set (mixtures of REE oxides and Fe2O3 + TiO2 as matrix), based on Latin hypercube sampling providing extremely low correlation (<0.03) between the content of different REEs, for the first time for LIBS measurements. Its applicability was assessed for univariate and multivariate (partial least squares regression) calibration models to solve the above problems. The content of each REE in the calibration set varies by two orders of magnitude and completely covers the concentration range in the independent test set of CRMs of natural REE-rich niobium and uranium ores. Selection of analytical lines was carried out through the thermodynamic modeling of LIBS spectra and helped to find the most intensive but not self-absorbed lines in very rich emission spectra of ores. This step greatly reduced the number of required experiments. Comparison of analytical performance of high- (0.03 nm) and low- (0.26 nm) resolution spectrometers coupled to a high-energy laboratory laser and high- (0.06 nm) resolution spectrometer coupled to a low-energy portable laser is presented. For the highest resolution spectra PLS-R models provide quantitative determination of Ce (0.046 – 3.95 %), La (0.026 – 2.41 %), Nd (0.015 – 1.18 %) and semi-quantitative determination of Sm (24–1500 ppm). The lowest resolution spectra and PLS-R allow semi-quantitative determination of La. For the system with portable laser PLS-R models provide determination of Ce (quantitative) and La (semi-quantitative). Pr and Nd were special cases due to considerable matrix effects for atomic lines, addressed by the use of ionic line of Nd for the highest resolution spectrometer. Reliable Pr ionic lines were not detected due to strong interference of matrix elements (Fe, Ti). Results show that LIBS has potential to quantify REEs in natural ores.
- Добавил в систему: Попов Андрей Михайлович
Прикрепленные файлы
| № | Имя | Описание | Имя файла | Размер | Добавлен |
|---|