Solid-state electrochemical analysis of Inka pottery from Qotakalli archeological site in the Cusco (Perú) area

A series of sherds from the archeological site of Qotakalli in the area of Cusco (Perú), corresponding to four different Inka periods, were studied by means of square wave voltammetry of immobilized particles (VIMP) and electrochemical impedance spectroscopy (EIS). Ceramic microparticles were placed on a graphite working electrode and were characterized by VIMP and EIS in contact with 0.10 M H 2 SO 4 aqueous electrolyte. Voltammetric features of the sherds, corresponding to the reduction of Fe(III) and Mn(IV) minerals and the oxidation of Fe(II), provided characteristic voltammetric features able to differentiate between different types of ceramic production and Inka periods. A consistent grouping was obtained from VIMP and EIS measurements, mainly responsive to porosity and microstructure variations of the ceramic samples, being also consistent with attenuated total reflectance—Fourier transformed infrared (ATR-FTIR) measurements, scanning electron microscopy (SEM), and optical and structural observations. Grouping of ceramic samples is important to support the archeological proposal of a diverse origin and production of pottery in Qotakalli.