Realization of a salt bridge-free microfluidic reference electrode

We report on the design of a microfluidic electrochemical cell with a true Ag/AgCl reference electrode that does not rely on a physical barrier or salt bridge, but instead takes advantage of slow diffusion times in micro-channels. The device concept is demonstrated in PDMS using the Ir+IV/Ir+III redox couple as an example. A scaling analysis provides limits of operation for the device.