Wired Microfabricated Electrochemical Systems

Metal wires have been used as an alternative to liquid junctions for the connection of solutions in microfabricated electrochemical devices. They exhibit similar performance to liquid junctions, provided that the interfacial potentials at both ends of the wires were appropriately canceled. Cyclic voltammograms of devices with liquid junctions and metal wires were very similar when no current or a low current flowed through the metal wire between the working and reference electrodes. Iridium wires with iridium oxide at both ends facilitated canceling of the interfacial potentials at either end of the junction particularly well, and were used effectively for voltammetry, amperometry, and potentiometry by adjusting the pH of the solutions in the working and reference electrode compartments to be equal. This approach was used to effectively integrate a reliable common reference electrode between multiple working electrodes and to conduct automated electrochemical control of solution transport in microfluidic systems.