RuO(2) pH Sensor with Super-Glue-Inspired Reference Electrode

A pH-sensitive RuO(2) electrode coated in a commercial cyanoacrylate adhesive typically exhibits very low pH sensitivity, and could be paired with a RuO(2) working electrode as a differential type pH sensor. However, such sensors display poor performance in real sample matrices. A pH sensor employing a RuO(2) pH-sensitive working electrode and a SiO(2)-PVB junction-modified RuO(2) reference electrode is developed as an alternative high-performance solution. This sensor exhibits a performance similar to that of a commercial glass pH sensor in some common sample matrices, particularly, an excellent pH sensitivity of 55.7 mV/pH, a hysteresis as low as 2.7 mV, and a drift below 2.2 mV/h. The developed sensor structure opens the way towards the development of a simple, cost effective, and robust pH sensor for pH analysis in various sample matrices.