Influence of Electrode Polishing Protocols, Potentiostat Models, and LOD Calculation Methods on the Electroanalytical Performance of SWV Measurements at Glassy Carbon Electrodes

The aim of this research is to present the extent to which the basic elements used in electrochemical measurements affect the results of electroanalytical procedures. Measurements were carried out using the square wave voltammetric technique on a glassy carbon electrode, and the recorded analytical signal corresponded to a model redox system. One of the objectives of the study was to illustrate the impact of using potentiostats from different manufacturers, as well as the variations observed among different models within the same brand. These models exhibited notable differences in both cost and advanced electrochemical measurement capabilities. The mechanical cleaning method for the solid disk electrode surface was also taken into consideration. Three different polishing motion types were tested, together with the number of repetitions. It was revealed that polishing motion significantly influences the electroactive surface area of the working electrode, as well as the repeatability of the measurements. The research showed that the largest electroactive surface area and the best repeatability of parameters are achieved when polishing is performed by drawing an 8-type motion on the polishing pad. The obtained results confirmed that the equipment and polishing applied in research have a greater than previously assumed impact on the statistical parameters characterizing the analytical procedure, for example, the limit of detection (LOD) or the dynamic range of the calibration curve. Both analyzed parameters have a significant impact on the quality of the statistical parameters describing derived analytical procedures. Finally, it was shown that significantly different statistical parameters can be obtained from the same set of data using various approaches for LOD estimation, with discrepancies reaching up to two orders of magnitude.