Microfluidic reference electrodes for applications in biosensing

A microfluidic Silver/Silver Chloride (Ag/AgCl) reference electrode was fabricated and operated in various modes. This micro-scale reference electrode design includes all the features of the macro-scale version including, Ag/AgCl electrode, inner standard solution and nanoporous membrane separator in a small form factor. This miniature reference electrode could also be operated in modes where the liquid junction potential can be stabilized to provide a stable potential. In one such mode, the microfluidic reference electrode with a free diffusion liquid junction shows <0.1 mV stability over a 100-hour lifespan and no sensitivity to pH and chlorine concentration of the external solution.