Design and analysis of a low-cost potentiostat for application with microbial electrochemical sensors

Potentiostats are often limited to relatively costly laboratory-based analysis, which limits their access and application by researchers and practitioners, including for mobile in-field systems. This paper presents an alternative low-cost potentiostat design, sufficiently accurate for application with a microbial electrochemical sensor. The design of the device is described, evaluated using simulation and applied to a microbial electrochemical sensor to measure acetate. Incorporated into the design are a micro-controller, local data storage, and a standard industrial communication protocol to provide flexibility and data management. The device was able to produce a potential at +/- 2.5 V relative to an Ag-AgCl reference electrode and to measure current at +/- 2 mA, which was comparable to the performance of laboratory potentiostats on the market. Simulation analysis using fundamental electronic principles, such as Ohm's Law, confirmed that operation of the system was valid and as expected. Further testing using a pseudo-cell showed the device was accurate across a relevant potential range. Results from the initial calibration of the device show less than 1.6 % standard error of the mean. The device was further applied to a microbial electrochemical cell to measure acetate, which confirmed the device was functional for this application and recorded values were consistent with expectations based on the relevant literature.