Issue 11, 2022

High-precision EPMA measurement of trace elements in ilmenite and reference material development

Abstract

Ilmenite occurs as a common accessory mineral in igneous and metamorphic rocks and is a major constituent in lunar basaltic rocks. The distributions and concentrations of major and trace elements in ilmenite have potential to record temporal changes in melt chemistry and crystal fractionation processes. However, such data are scarce because of the limitations of in situ microanalytical technology, the lack of reference materials for trace elements, and the difficulties in analyzing the small needle-like shape of ilmenite. In this study, a natural ilmenite sample derived from the Panzhihua Fe–Ti–V oxide ore deposit was characterized for its major and trace elements in relation to the potential use as reference material. The homogeneity of the studied ilmenite (PZH12-09) was assessed by electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS). It is homogeneous with relative standard deviation (RSD) values within ±3.76% for major elements (Fe, Ti, Mg, and Mn) and ±12.6% for trace elements (Sc, V, Cr, Co, Ni, Zr, Nb, Hf, and Ta), respectively. The relative deviations for major and trace elements determined by solution-mode ICP-MS and in situ microanalysis range from 0.11% to 7.71%, suggesting that the PZH12-09 ilmenite can be used as a reference material for in situ microanalysis. Furthermore, we developed a high-precision EPMA method to simultaneously determine the major and trace elements of ilmenite. The disadvantage of high detection limits and poor accuracy in trace element analyses were overcome by optimizing the analytical conditions, including the accelerating voltage (20 kV), beam current (200 nA), use of large Bragg crystals (LPET and LLIF), aggregate intensity counting, peak overlap and secondary standard corrections. The measured concentrations of most trace elements are consistent within 10% relative deviation compared with the reference values. The RSD values were within ±15% at various concentrations of trace elements (except for Ni and Nb), indicating the high accuracy and precision characteristics of the EPMA methodology. Detection limits for the trace elements vary from 11 to 27 μg g−1 (3σ). The developed method should provide robust trace element data for both extraterrestrial and terrestrial ilmenite samples at high spatial resolution (1–2 μm).

Graphical abstract: High-precision EPMA measurement of trace elements in ilmenite and reference material development

Supplementary files

Article information

Article type
Paper
Submitted
10 7月 2022
Accepted
26 9月 2022
First published
29 9月 2022

J. Anal. At. Spectrom., 2022,37, 2351-2361

High-precision EPMA measurement of trace elements in ilmenite and reference material development

L. Jia, Q. Mao, H. Tian, L. Li, L. Qi, S. Wu, J. Yuan, L. Huang and Y. Chen, J. Anal. At. Spectrom., 2022, 37, 2351 DOI: 10.1039/D2JA00238H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements