Figure 5
Response of potential difference (open squares) to ionic current changes (dashed lines) for samples with pH 1.68 (a), 4.01 (b), 6.86 (c), and 9.18 (d). The mixed solution in one side of the double-barreled glass micro-electrodes consists of 1.0 × 10−2 mol/K KCl and pH 4.01 buffer solutions and that in the other side is a 1.0 × 10−2 mol/L KCl solution. I-V characteristics associated with a–d (e). The potential differences at ± 1.0 nA relative to 0 nA as a function of pH are also shown in the inset.
