To verify this simulation model, CV scans were conducted in PB solutions, starting with two different initial pH (pH 7.4 and pH 6.8). The CVs were undertaken within a potential range of -0.2 to 1 V versus on-chip Pt RE at a scan rate of 50 mV/s. During these tests, a steady potential was applied to the protonator electrodes. In these experiments, the generation of protons was carried out using a potentiostatic method, rather than a galvanostatic method to provide better control over the potential of the protonator IDEs. Fig. and d presents the complete CV curves of the gold oxide reduction peaks under two different initial pH conditions (pH 7.4 for the buffer and pH 6.8 for artificial saliva), represented by black curves and chemically prepared PB solution at pH 5.5 (red curves) along with the chemically controlled pH 5.5 (blue curves). The in-situ measurement of solution's pH was performed by utilizing the potential minima of the Au2O3 reduction peaks as an indicator of pH. Moreover, it can be observed that from the figures (insets), the initial potential minima of the gold oxide reduction peaks for the solutions with pH values of 7.4 and 6.8 were at 0.04 V and 0.06 V, respectively. By contrast, for the pH 5.5 solutions, the peak minima shifted more anodically to 0.08 V arising from a consistent shift in the peak voltage of the Au2O3 reduction (Seymour et al., 2020). Notably, the solutions with initial pH 7.4 (buffer) and pH 6.8 (artificial saliva) electrochemically controlled to pH 5.5 also shifted anodically to 0.08 V.