Liquid junction potential in the pH measurement and microfluidic pH measurement device using ISFET sensor

We investigate a liquid junction (LJ) used in the reference electrode for potentiometry. The LJ device is essential in the pH measurement using glass electrode or ion-sensitive field-effect transistor (ISFET). Though traditional and reliable, the conventional LJ devices have some unsolved problems. First, we explain about a common type LJ device, then reconsider two types of pH measurement device we have previously reported, next consider a new LJ device using ISFET sensors.