Pyrite/pyrrhotite mineral based electrochemical sensor for redox determination in aqueous media

Abstract

The characterization, construction and performance characteristics of a novel sensor have been carried out. With this purpose, an accurate characterization of the mineral has been performed using scanning electron microscopy (SEM/EDX), X-ray spectrometer and potentiometry. The elemental composition of the sample has been obtained by X-ray microanalysis. The main compounds of the mineral are a pyrite and a pyrrhotite. The potentiometric analysis has allowed investigating some properties of the pyrite/pyrrhotite mineral as a potential sensor material. This technique has also been useful to investigate possibility of using this mineral as indicator electrode for redox determination in aqueous solution. The sensor based on pyrite/pyrrhotite mineral as an electroactive material, displays a stable, reproducible and linear response for iron(III) over concentration range of 10-6-10-1 mol/L with non-Nernstian slope of 38.7 ± 0.6 mV per decade. The response time was 10 s. The proposed sensor was applied to determine cobalt(II) and the results were compared with that of a platinum electrode. The determination of 2 mg of cobalt(II) shows an average recovery of 100.9%. The relative standard deviation of this method was 0.5%.