Reusability of RuO2-Nafion electrodes, suitable for potentiometric pH measurement

Nafion™ (Nafion) membrane is known to improve the performance of the electrochemical sensors by acting as a semi-permeable barrier when applied on the electrode’s surface. However, the Nafion membrane is soft and can degrade with time. In order to see if the Nafion membrane can be cast repeatedly, we investigated the reusability of Nafion-covered electrodes. In this paper, we present the results of the investigation of the performance of the potentiometric pH-electrodes, based on Ruthenium(IV) oxide (RuO2), that were covered with Nafion membrane several times. The electrodes were fabricated by screen printing method and modified with Nafion by drop-casting technique. The investigation of the performance was based on the evaluation of the most important electrode characteristics: sensitivity and linearity, hysteresis, and drift. We have demonstrated that the screen printed RuO2 electrodes show excellent electrochemical characteristics at room temperature even after coating them with Nafion for the third time.