Oxidation-reduction potentialFor a water body, there are often multiple redox pairs that form a complex redox systemOxidation-reduction potentialIt is the comprehensive result of oxidation-reduction reactions between various oxidizing and reducing substances. Although this indicator cannot be used as a measure of the concentration of certain oxidizing and reducing substances, it can help us understand the electrochemical characteristics of water bodies, analyze their properties, and is a comprehensive indicator.

Water bodies must be measured on-site. The measurement method is to use a platinum electrode as the indicator electrode, a saturated calomel electrode as the reference electrode, and a water sample to form a primary cell. The platinum electrode is measured relative to the calomel electrode using a transistor millivoltmeter or a universal pH meter, and then converted to relative to the standard hydrogen electrode as the report result.

The calculation formula is as follows:
E_n=E_ind+E_ref
In the formula: En - water sample (mV);
E_ind——Measured (mV);
E_ref——The electrode potential (mV) of a saturated calomel electrode at a certain temperature can be found in physical and chemical manuals or relevant materials.