Finding a needle in a haystack: quantitative HERFD-XRF imaging and HERFD-XANES characterization of trace platinum in gold solidi from the Late Roman and Byzantine Empires

Journal Article · Mon Nov 25 00:00:00 EST 2024 · Journal of Analytical Atomic Spectrometry

DOI:https://doi.org/10.1039/D4JA00281D· OSTI ID:3017090

Van Loon, Lisa L. ^[1]; Finfrock, Y. Zou ^[2]; Meira, Debora Motta ^[3]; Burgess, R. W. ^[4]; Bevan, George ^[5]; Banerjee, Neil R. ^[6]

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1. Western University, London, ON (Canada); LISA CAN Analytical Solutions Inc., Saskatoon, SK (Canada)
2. Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
3. University of Saskatchewan, Saskatoon, SK (Canada). Canadian Light Source, Inc.
4. University of Ottawa, ON (Canada)
5. Queen's University, Kingston, ON (Canada)
6. Western University, London, ON (Canada)

High-Energy Resolution Fluorescence Detection X-Ray Fluorescence (HERFD-XRF) imaging and HERFD X-ray Absorption Near Edge Structure (XANES) spectroscopy are used to quantify and characterize trace platinum (Pt) in gold solidi from the Late Roman and Byzantine Empires. Historically, the elemental analysis of coins has been pivotal in distinguishing authentic artifacts from forgeries, elucidating minting practices, and understanding economic shifts. Notably, a new gold source with high platinum content appeared in the fourth century CE, transforming the Roman economy. Traditional methods struggled to detect platinum due to the overwhelming gold matrix. Here, this study demonstrates the effectiveness of HERFD techniques in resolving this challenge. Three gold solidi, minted between 654 and 659 CE, were analyzed alongside reference gold materials with known Pt concentrations. The HERFD-XRF imaging revealed spatial distributions of platinum, highlighting non-uniformities within the coins. Additionally, HERFD-XANES spectroscopy identified the oxidation states and chemical speciation of platinum. Results demonstrate that platinum in the solidi primarily exists as metallic Pt, with some surface oxidation. The findings align with previous measurements but reveal higher Pt concentrations and significant inhomogeneities. This research confirms the reliability of HERFD methods for quantifying trace elements and provides new insights into the raw material sources and minting techniques of ancient gold coins. The non-destructive nature of this approach allows for extensive analyses, offering valuable data for historical, economic, and archaeological studies. This innovative application of HERFD-XRF imaging and XANES in cultural heritage research underscores the potential for detailed material characterization and conservation, enhancing our understanding of ancient economies and trade patterns.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 3017090
• Alternate ID(s): OSTI ID: 2478732
• Journal Information: Journal of Analytical Atomic Spectrometry, Journal Name: Journal of Analytical Atomic Spectrometry Journal Issue: 1 Vol. 40; ISSN 0267-9477; ISSN 1364-5544
• Publisher: Royal Society of Chemistry
• Country of Publication: United States
• Language: English