CMOS VLSI Potentiostat for Portable Environmental Sensing Applications

This paper reports an integrated CMOS potentiostat for detection of heavy metal ions in water and other solvents based on electrochemical sensing. The proposed potentiostat features a low-input impedance, high sensitivity, high gain and low power transimpedance amplifier front end, with programmable control of electrode potential, thus facilitating continuous bidirectional measurement of reduction-oxidation (redox) current in a potentiostat for cyclic voltammetry (CV) experiment. For proof of concept, we use the proposed integrated potentiostat to perform CV on a reference ferricyanide (K₃Fe(CN)₆) using external microelectrodes. Results compared with standard benchtop potentiostat confirm microelectrode behavior with accurate estimate of redox potential with varying redox currents proportional to the ferricyanide concentration.