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An Iterative Qualitative–Quantitative Sequential Analysis Strategy for Electron-Excited X-ray Microanalysis with Energy Dispersive Spectrometry: Finding the Unexpected Needles in the Peak Overlap Haystack

Published online by Cambridge University Press:  03 September 2018

Dale E. Newbury  and
Nicholas W. M. Ritchie
Dale E. Newbury
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
Nicholas W. M. Ritchie*
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
*
*Author for correspondence: Nicholas W. M. Ritchie, E-mail: [email protected]
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Abstract

When analyzing an unknown by electron-excited energy dispersive X-ray spectrometry, with the entire periodic table possibly in play, how does the analyst discover minor and trace constituents when their peaks are overwhelmed by the intensity of an interfering peak(s) from a major constituent? In this paper, we advocate for and demonstrate an iterative analytical approach, alternating qualitative analysis (peak identification) and standards-based quantitative analysis with peak fitting. This method employs two “tools”: (1) monitoring of the “raw analytical total,” which is the sum of all measured constituents as well as any such as oxygen calculated by the method of assumed stoichiometry, and (2) careful inspection of the “peak fitting residual spectrum” that is constructed as part of the quantitative analysis procedure in the software engine DTSA-II (a pseudo-acronym) from the National Institute of Standards and Technology. Elements newly recognized after each round are incorporated into the next round of quantitative analysis until the limits of detection are reached, as defined by the total spectrum counts.

Keywords

qualitative X-ray analysisenergy dispersive X-ray spectrometryscanning electron microscopystandards-based analysisquantitative X-ray microanalysis
Type
Materials Science Applications
Information
Microscopy and Microanalysis , Volume 24 , Issue 4 , August 2018 , pp. 350 - 373
Copyright
© Microscopy Society of America 2018 

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