This voltage potential is a function of the free acidity or free alkalinity of the solution. The pH element is permeable by H+ ions, and the pH electrode is filled with neutral solution, which by ...

We have just begun to learn how to use nature's pH meter. Modi, S. et al. A DNA nanomachine that maps spatial and temporal pH changes inside living cells. Nat. Nanotechnol. 4, 325–330 (2009).

Universal indicator is a mixture of a variety of other indicators and can be used to measure the approximate pH of a solution. A more accurate value can be obtained using a pH probe.

This implies parallel measurement of pH and conductivity with 914 pH/Conductometer, and parallel recording of two pH values with the 913 pH Meter. Measurements can be performed in different locations ...