Quantitative energy dispersive X-ray analysis of submicrometric particles using a scanning electron microscope

Area of Science:

• Geochemistry
• Materials Science
• Analytical Chemistry

Background:

• Quantitative scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis is crucial for elemental composition determination.
• Particle effects, including absent mass and reduced absorption, introduce significant errors in SEM-EDX quantification.
• Accurate elemental analysis of geological samples like hornblende and augite requires addressing these particle-induced errors.

Purpose of the Study:

• To minimize errors in quantitative SEM-EDX analysis caused by particle effects in submicrometric geological samples.
• To determine correction factors as a function of fragment size for key elements (O, Na, Mg, Si, Ca, Fe).
• To evaluate the influence of matrix effects on correction factors for geological standards.

Main Methods:

• Quantitative SEM-EDX analysis was performed on submicrometric particles of hornblende and augite.
• Correction factors were derived to account for absent mass and reduced absorption effects based on fragment size.
• The impact of standard composition (matrix effect) on correction factors was systematically evaluated.

Main Results:

• Absent mass effect was dominant for most elements, while reduced absorption dominated for light elements (O, Na).
• No significant matrix effect was observed on the correction factors.
• Corrected SEM-EDX data yielded quantification errors below 3% for light elements and below 2% for heavy elements (e.g., ~1% for Fe).

Conclusions:

• The developed correction factors effectively minimize particle effects in SEM-EDX analysis of geological materials.
• Accurate elemental quantification is achievable with high precision for both light and heavy elements.
• This methodology enhances the reliability of SEM-EDX for analyzing fine-grained geological samples.