Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 03, 2023 - September 06, 2023
In a previous study, we proposed a novel pH measurement method using a double-barrelled glass microelectrode in which a pH buffer solution and KCl solution were maintained in a glass capillary with a Ag-AgCl wire for the counter and reference electrodes. Applying a galvanostatic current between the counter electrode and the working electrode which was separately in another glass capillary, pH values of sample solutions were identified from the asymmetric current-voltage characteristics. In the present study, the working, counter, and reference electrodes are isolated from each other using a triple-barrelled glass microelectrode to improve the measurement accuracy. Furthermore, a theoretical model is developed to explain the ionic current rectification caused by the asymmetric electrokinetic transport at the interface between the inner and outer solutions, where the electrophoretic transport of protons in applied electric fields and diffusion caused by the concentration gradient of protons are balanced. As a result, the experimental results are deeply understood from the viewpoint of the ion transport phenomena in nanoscale.
