The rH index for quality and environmental controls: standards and application procedures

The quantity rH, an index of the reducing power of a redox system is, in conceptual and operational terms, coordinatively linked with the two familiar electroanalytical quantities: redox potential (EO/R) and pH, and has recently become important in quality and environmental controls (hydrographic network, human consumption waters, industrial effluents, etc.). It has some significant problems of standardization and methodological applications, especially on passing from pure water medium to aqueous-organic media, and the results of the most recent researches are here presented.