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 ?
1) we installed piezometer clusters to measure depth to water table at 0.5, 1.0, 1.5, and 4.0m below ground level (bgl); platinum electrodes to measure soil redox potential at 0.2, 0.5, 1.0, and 2.0 m bgl; and soil solution samplers at 0.2, 0.5, 1.0, and 4.0 m bgl.
Sample Major phases Minor phases Copper concentrate Chalcopyrite Pentlandite (leach residue) ([CuFeS.sub.2]) [[(Fe Ni).sub.9] [S.sub.4]] Hydronium jarosite [[H.sub.3]o [Fe.sub.2] [([SO.sub.4)].sub.3] O[H.sub.6])] Table 5: Redox potentials of the pulp during bacterial leaching (Tf- 44).
Effect of fluctuating rhizosphere redox potential on carbon assimilation of Spartina alterniflora.
In all the samplings, the redox potential in the deepest layers decreases rapidly to reach a maximum value of reduction (-315 [+ or -] 83 mV) at 50 mm depth.
To convert the magnitude of the redox potential change into some measure of energy, use the following equation:
Redox potential was measured with platinum electrodes constructed by welding 1.5 cm of 1-mm-diameter platinum wire to insulated, solid copper wire and sealing it with epoxy resin so that only bare platinum wire was in contact with soil (DeLaune et al.
Thus, oxidation of the media redox potential in the absence of cells reflected a decrease in Cys rather than an increase in CySS (Figures 2(a) and 2(b)).
Unlike hydroquinone the redox potential of L-cysteine in the pH range of our study is not affected as much.
The facts of solubility of Cd varying with soil redox potential and the greater availability of As under anaerobic condition than aerobic environment support the possibility of reducing As and Cd accumulation in rice grain through water management [14,15].
It has also been shown that the redox potential of adsorbed dye depends on the pH of the electrolyte and on the potential applied to the semiconductor [5].
The sequence of electron acceptors used as the redox potential decreases is well described in the literature (Patrick and Reddy 1978; Marschner 1995; Fageria et al.