Archaeometric analysis of Roman bronze coins from the Magna Mater temple using solid-state voltammetry and electrochemical impedance spectroscopy

Francesca Di Turo; Noemí Montoya; Joan Piquero-Cilla; Caterina De Vito; Fulvio Coletti; Gabriele Favero; Antonio Doménech-Carbó

doi:10.1016/j.aca.2016.12.007

Archaeometric analysis of Roman bronze coins from the Magna Mater temple using solid-state voltammetry and electrochemical impedance spectroscopy

Anal Chim Acta. 2017 Feb 22:955:36-47. doi: 10.1016/j.aca.2016.12.007. Epub 2016 Dec 26.

Authors

Francesca Di Turo¹, Noemí Montoya², Joan Piquero-Cilla², Caterina De Vito¹, Fulvio Coletti³, Gabriele Favero⁴, Antonio Doménech-Carbó⁵

Affiliations

¹ Department of Earth Sciences, Sapienza University of Rome, P.le Aldo Moro 5, Rome, Italy.
² Departament de Química Analítica, Universitat de València, Dr. Moliner, 50, 46100, Burjassot, València, Spain.
³ Soprintendenza Speciale per il Colosseo, il Museo Nazionale Romano e l'Area Archeologica di Roma, P.zza dei Cinquecento 67, Rome, Italy.
⁴ Department of Chemistry and Drug Technologies, Sapienza University of Rome, P.le Aldo Moro 5, Rome, Italy.
⁵ Departament de Química Analítica, Universitat de València, Dr. Moliner, 50, 46100, Burjassot, València, Spain. Electronic address: antonio.domenech@uv.es.

PMID: 28088279
DOI: 10.1016/j.aca.2016.12.007

Abstract

Voltammetry of microparticles (VMP) and electrochemical impedance spectroscopy (EIS) techniques, complemented by SEM-EDX and Raman spectroscopy, were applied to a set of 15 Roman bronze coins and one Tessera from the temple of Magna Mater (Rome, Italy). The archaeological site, dated back between the second half and the end of the 4th century A.D., presented a complicated stratigraphic context. Characteristic voltammetric patterns for cuprite and tenorite for sub-microsamples of the corrosion layers of the coins deposited onto graphite electrodes in contact with 0.10 M HClO₄ aqueous solution yielded a grouping of the coins into three main groups. This grouping was confirmed and refined using EIS experiments of the coins immersed in air-saturated mineral water using the reduction of dissolved oxygen as a redox probe. The electrochemical grouping of coins corroborated the complex stratigraphy of the archaeological site and, above all, the reuse of the coins during the later periods due to the economic issues related to the fall of the Roman Empire.

Keywords: Bronze; Electrochemical impedance spectroscopy; Roman coins; Voltammetry of microparticles.