redox potential


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ox·i·da·tion-re·duc·tion po·ten·tial (E0+),

the potential in volts of an inert metallic electrode measured in a system of an arbitrarily chosen ratio of [oxidant] to [reductant] and referred to the normal hydrogen electrode at absolute temperature; it is calculated from the following equation; where R is the gas constant expressed in electrical units, T the absolute temperature (Kelvin), n the number of electrons transferred, F the faraday, and E0 the normal symbol for the potential of the system at pH 0; for biologic systems, E0' is often used (in which pH = 7). Compare: Nernst equation.
Synonym(s): redox potential

redox potential

a quantitative measurement of the willingness of an electron carrier to act as a red ucing or ox idizing agent. Redox potential is measured in volts; the more negative the value, the better the carrier will act as a reducing agent. Thus, in an ELECTRON TRANSPORT SYSTEM the carriers are arranged in order of increasing redox potentials (negative to positive). For example, in Fig. 211 ferredoxin has a lower (more negative) redox potential than plastoquinone which has a higher value (less negative).
References in periodicals archive ?
Grable and Siemer (1968) presented a relationship between redox potential (Eh) and oxygen concentration (%).
Investigating mitochondrial redox potential with redox-sensitive green fluorescent protein indicators.
Mean redox potential of potting medium for flooded plants varied from + 67 mV to -297 mV for mahogany and from + 189 mV to - 260 mV for pond apple indicating that hy poxic conditions existed in the root zones of flooded plants within 2 d after flooding in both experiments.
Other reason for biological acceleration of galvanic interaction was the chelation of cysteine secreted by Tf with pyrite, which altered the redox potential of Fe2+:Fe3 couple, thus accelerating the oxidation of pyrite sulfides as + indicated by Rojas and Tributsch, (2001).
Samplings were done twice per month from April to August: redox potential (Eh, in mVolt) is a chemical indicator for the quality of superficial layer of sediment.
A correlation has been observed between the redox potential and anticancer activity for Cu chelates of elesclomol and its analogs, suggesting that the ability to promote redox cycling of Cu(II) to Cu(I) is necessary for anticancer activity.
Redox potential (Eh) was determined in the wet soils at 0, 7, 14, and 21 days after imposition of treatments and during recovery periods.
To provide an indication of soil oxygen content, soil redox potential was measured with a metallic combination electrode (Accumet Model 13-620115, Fisher Scientific, Pittsburgh, PA) attached to a portable volt/pH meter (Accumet model AP62, Fisher Scientific, Pittsburgh, PA).
Whole fresh and dried fruits were assessed for phenolics, ascorbic acid, antioxidant activity and redox potential.
Redox potential did not exhibit any discernable pattern; it was generally high, ranging from 200--400 mV.
The lowest pH and redox potential under submerged conditions were observed for the clay soils but pH and redox potential were not limiting to the growth of rice for any soil (Table 2).