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Updated: Jun 20, 2026
14:53
In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis
Published on: February 3, 2018
Quantitative electron probe microanalysis of nonconducting specimens: science or art?
Guillaume F Bastin1, Hans J M Heijligers
1Laboratory of Solid State and Materials Chemistry, University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands. g.f.bastin@tue.nl
Summary
Insufficient electrical conductivity in oxides significantly impacts quantitative electron probe microanalysis by causing surface charging and altering X-ray signals. This effect is particularly pronounced for light elements like oxygen, leading to inaccurate results.
Area of Science:
- Materials Science
- Analytical Chemistry
- Geochemistry
Background:
- Quantitative electron probe microanalysis (EPMA) is crucial for determining elemental composition.
- Non-conductive samples in EPMA can suffer from surface charging, affecting X-ray signal detection.
- Accurate analysis of light elements, such as oxygen, is often challenging due to charging effects.
Purpose of the Study:
- To investigate the impact of insufficient electrical conductivity on quantitative EPMA results for oxides.
- To study how surface charging affects emitted X-ray signals in EPMA.
- To evaluate the influence of conductive coatings on interelement X-ray intensity ratios.
Main Methods:
- Investigated several oxide samples with varying electrical conductivity.
- Studied the effects of surface charging on emitted X-ray signals.
- Applied conductive coatings (carbon, copper) to samples and analyzed their effect on X-ray intensity ratios.
- Utilized phi (pz) software for quantitative analysis of oxygen in hematite (Fe2O3) standards.
Main Results:
- Conductive coatings (carbon, copper) alter interelement X-ray intensity ratios, regardless of coating thickness.
- These alterations are more significant for light elements like oxygen, showing strong variations with coating thickness.
- Quantitative analysis of oxygen on uncoated, well-conducting oxides yielded excellent results.
- Coated, non-conducting specimens produced widely scattering and non-coherent results, attributed to conductivity issues.
Conclusions:
- Lack of sufficient electrical conductivity is a primary cause of discrepancies in quantitative EPMA of oxides.
- Surface charging effects are critical and can lead to significant errors, especially for light elements.
- Careful consideration of sample conductivity and potential charging mitigation strategies is essential for accurate EPMA analysis.
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