Construction and Metrological Characterization of a Minimal Instrumentation Micropolarograph

What is it about?

A minimal instrumentation micropolarograph was built, and its metrological characterization was performed. The oxidation of K4[Fe(CN)6] was studied by linear voltammetry. A microdisc and a bar of carbon were used as working and auxiliary electrodes, respectively. A bar divided into compartments of copper-internal solution-cotton was used as reference. The linear coefficient of determination between the limiting current and the concentration was 0.9926, in the range of 10-2 - 10-1 mol L-1. The coefficient of variation of ten voltammograms at 0.08 mol L-1 was 1.8 %, being inferior to the maximum value reported for these methods. Mood and Kruskal-Wallis tests did not show significant differences between voltammograms. In the range of linear correlation coefficients of potential sweep 0.9488 to 0.9989, no sweep influence on voltammograms was observed. The expanded uncertainty associated with the determination of the limiting current was 1.9 µA. The linear voltammograms for oxidation of ascorbic acid and KI were obtained, showing correspondence with the reported results.

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Photo by National Cancer Institute on Unsplash

Photo by National Cancer Institute on Unsplash

Why is it important?

This work demostrates the reliability of using a ultra-low-cost homemade micropotentiostat for voltammetry.