CHARMed PyMca, Part II: An evaluation of interlaboratory reproducibility for ED-XRF analysis of copper alloys

A. Heginbotham*, D. Bourgarit, J. Day, J. Dorscheid, J. Godla, L. Lee, A. Pappot, D. Robcis

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


CHARMed PyMca is a protocol for researchers using energy-dispersive X-ray fluorescence spectroscopy (ED-XRF) who wish to maximize interlaboratory reproducibility of quantitative results from copper alloys found in heritage materials. This paper reports the results of a study evaluating the interlaboratory reproducibility expected when following this protocol. Five institutions participated in this study, using nine tube-based instruments of seven types. A set of 12 reference materials not used for calibration was analysed according to the protocol. The results show an improvement in reproducibility of between 65% and 83%, depending on the element, in comparison with a similar study carried out in 2010. The protocol allowed the consistent reporting of concentrations for 15 elements, in contrast to only eight elements that were reported in the 2010 study. Finally, the protocol was shown to generate accurate quantitative results with a well-characterized precision. It is hoped the information presented here can help researchers studying heritage copper alloys to collaborate more effectively and with greater confidence in the reproducibility of their results. It should also aid researchers to make realistic and informed decisions about whether or not the degree of reproducibility that they may expect from ED-XRF makes the protocol suitable for their specific purposes.

Original languageEnglish
Pages (from-to)1333-1352
Number of pages20
Issue number6
Early online date18 Jul 2019
Publication statusPublished - 1 Dec 2019


The authors thank V. Armando Sol? for ongoing support and assistance with PyMca; Nick Barbi of XGLabs for arranging the loan of the Elio spectrometer to the Getty Conservation Institute; Donna Corbin, Beth Price and Andrew Lins at the Philadelphia Museum of Art for their generous support; and Robert Van Langh at the Rijksmuseum, Amsterdam, his inspiration and for support. Part of the research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement n? 319209.

FundersFunder number
Seventh Framework Programme
Engineering Research Centers319209
European Research Council
Seventh Framework Programme


    • calibration
    • copper
    • fundamental parameters
    • reproducibility
    • XRF


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