A methodology for dating archeological lead artifacts based on the voltammetry of microparticles is described. This methodology is based on the comparison of the height of specific voltammetric features from PbO(2) and PbO corrosion products formed under long-term alteration conditions. Calibration of the method was performed with the help of a series of well-documented lead pieces from the funds of different museums of the Comunitat Valenciana (Spain) covering from the fifth century B.C. to present day. The variation of peak currents with the time of corrosion can be fitted to the same potential rate law as that found by Reich (α = 0.070 ± 0.005), using measurements on the Meissner fraction in the superconducting state of lead. The proposed electrochemical methodology enables the dating of archeological lead artifacts with a time-dependent uncertainty estimated to be ±150 years for the most ancient samples in this study.

An essentially non-invasive electrochemical methodology addressed to the authentication of archaeological lead is described. The method is based on the record of the voltammetric response of nanosamples from the archaeological artefact mechanically transferred to a graphite 'pencil' electrode in contact with aqueous buffers. Three diagnostic criteria for authentication are described based on the appearance of: (i) oxidative dissolution signals for trace metals like copper, arsenic, antimony and, often, tin and silver accompanying stripping peaks for lead, (ii) peak potential shifts for reduction peaks for patination products, and (iii) the presence of reduction peaks for PbO 2 . The method is applied to the authentication of an Iberian lead plate from the Tossal de Sant Miquel (Llíria, Spain) site using a series of genuine and false pieces from different provenances in the Valencian region (Spain).

The application of the voltammetry of microparticles methodology to date archaeological lead artifacts, based on the time-dependent formation of different layers of lead oxides, whose relative amount can be estimated from polarization curves and electrochemical impedance spectroscopy (EIS), is presented. This approach is complemented by additional data using square wave voltammetry data. Calibration of the method was performed with the help of a series of welldocumented, lead pieces from the funds of different Spanish museums, covering since the 7th century BC to nowadays.

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ABSTRACT:A method for identifying the vegetal species in wooden objects using microextractionassisted voltammetry of microparticles is described.