Redox Potential Imaging Sensor

Abstract
We developed a chemical imaging sensor which can be used to visualize the spatial distribution and temporal evolution of redox potential in chemical reaction systems. It is based on the light-addressable potentiometric sensor (LAPS), in which the insulating surface is found to be sensitive not only to the pH value but also to the redox potential of the adjacent electrolyte: a voltage shift of 50.3 mV/decade was observed for the [K3Fe(CN)6]/[K4Fe(CN)6] system. We show that it is possible to measure the distribution of redox potential with high speed (22 s for 64×64 pixels) using this sensor.