Construction of Platinum Electrodes

The principles associated with the Nernst equation form the basis for developing electrodes to measure electron activity or electrical potential. The electrochemistry based on the electrode potential is related to ion activities, which results in the development of specific ion electrodes. There are several commercially available electrodes designed to measure Eh, pH, and specific ion activities. In this section we will present simple methods to construct redox electrodes for use in the laboratory and under field conditions. Many commercially available electrodes are bulky and are not suitable for use under field conditions. For the past three decades methods associated with the construction of redox electrodes were developed in our laboratories. 

Field electrodes are typically made with platinum wire with a diameter of 1.024 mm cut into 

FIGURE 4.7 Schematic showing the construction and installation of field electrodes. (1) Platinum wire of 1.024 mm diameter, (2) waterproof epoxy, (3) copper wire, (4) heat-shrinking insulation, (5) reference electrode, (6) voltmeter, and (7) electrodes installed at different depths. 

---