SweepStat: A Build-It-Yourself, Two-Electrode Potentiostat for Macroelectrode and Ultramicroelectrode Studies

Experimental electrochemistry offers unique opportunities for interactive instruction at all levels of education; however, widespread adoption in curricula is hindered by high costs associated with electrochemical instrumentation. Thus, the development of affordable instruments represents an essential step toward making electrochemistry accessible to everyone. While numerous commercially available three-electrode potentiostats exist, two-electrode potentiostats provide a simple and inexpensive alternative. Herein, we present the two-electrode SweepStat as a low-cost option capable of performing voltammetry and amperometry with comparable data acquisition to commercially available potentiostats valued from $4,000-40,000 USD. Additionally, the SweepStat's design facilitates current measurements in the nanoampere regime, permitting experiments with ultramicroelectrodes (UMEs; r(eleorode) < 25 mu m). The fabrication, programming, and testing of this device constitute a valuable experimental exercise at the intersection of circuit design and construction, computer programing, and electrochemical analysis. A set of simple electrochemical experiments are presented for both macroelectrodes and UMEs, highlighting key electrochemical techniques, equations, and concepts. Furthermore, finite element modeling and commercial potentiostat comparisons are used to verify the efficacy of the SweepStat platform. The open-source nature of the SweepStat coupled with the wealth of electrochemical techniques and experiments that can be implemented with a simple two-electrode circuit offers an unparalleled opportunity for electrochemical instruction with extensive method development driven by student research.