All-solid-state Reference Electrodes for analytical applications

The increasing development of electrochemical wearable and Lab-On-a-Chip (LOC) sensors have created the urgent need of efficient and stable miniaturized Reference Electrodes (REs). Ag/AgCl REs are the simplest, most common and environmental friendly REs. Conventional liquid-filled REs are not suitable for the portable applications because of the difficult trapping of the solution in miniaturized electrodes and of the high sensitivity to temperature and pressure variations. In recent years several attempts to build all-solid-state REs have been proposed in literature. However, many challenges still need to be overcome before reaching the commercialization stage, including the continuous leaching of the loaded ions and the influence of the sample solution on the interfacial potential. In this paper, we investigate and compare different routes to fabricate solid- contacts REs. The produced REs are used for the calibration of nanostructured potentiometric sensors. The different stability at various chlorides concentrations and pH is also investigated. Finally, their voltammetric response is compared to a Double Junction (DJ) RE.