Determination of reduction potentials and electron transfer stoichiometries for biological redox species by thin-layer pulse and staircase coulometry

1981 ◽  
Vol 53 (4) ◽  
pp. 594-598 ◽  
Author(s):  
Chih-Ho. Su ◽  
William R. Heineman
Keyword(s):  
Electron Transfer ◽  
Thin Layer ◽  
Redox Species ◽  
Reduction Potentials

On the Determination and Use of Reduction Potentials of Short-Lived Radicals. A Review

2000 ◽  
Vol 65 (6) ◽  
pp. 829-843 ◽  
Author(s):  
Henning Lund ◽  
Karen Skov ◽  
Steen Uttrup Pedersen ◽  
Torben Lund ◽  
Kim Daasbjerg
Keyword(s):  
Aqueous Solution ◽  
Electron Transfer ◽  
Reaction Mechanisms ◽  
Nucleophilic Attack ◽  
Grignard Reaction ◽  
Hydroxide Ion ◽  
Reduction Sequence ◽  
Reduction Potentials ◽  
Srn1 Reaction

A method, the "competition method", for the determination of reduction potentials and estimation of standard potentials for short-lived radicals is reviewed. Applications of the reduction potentials of radicals as arguments for reaction mechanisms are presented for the Grignard reaction, the photoreduction of ketones with alcohols, and the SRN1 reaction. Reductions induced by hydroxide ions are discussed in more detail, and the classic reaction between nitrosobenzene and hydroxide ion in aqueous solution is used as an example of such a reaction. A nucleophilic attack by hydroxide ion rather than an electron transfer initiates the reduction sequence. A review with 26 references.

Dissociative electron transfer in polychlorinated aromatics. Reduction potentials from convolution analysis and quantum chemical calculations

2016 ◽  
Vol 18 (32) ◽  
pp. 22573-22582 ◽  
Author(s):  
Piotr P. Romańczyk ◽  
Grzegorz Rotko ◽  
Stefan S. Kurek
Keyword(s):  
Electron Transfer ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Redox Potentials ◽  
Dissociative Electron Transfer ◽  
Reduction Potentials ◽  
Polychlorinated Benzenes

The combination of convolution analysis and quantum-chemical calculations at DFT and CCSD(T)-F12 levels allows the determination of standard redox potentials and the mechanism type of dissociative ET in environmentally relevant polychlorinated benzenes.

Development of a method for multielemental determination in water by EDXRF with radioisotopic source of 238Pu.

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Camilo Fuentes Serrano ◽  
Juan Reinaldo Estevez Alvares ◽  
Alfredo Montero Alvarez ◽  
Ivan Pupo Gonzales ◽  
Zahily Herrero Fernandez ◽  
...  
Keyword(s):  
Thin Layer ◽  
Expanded Uncertainty ◽  
Considerable Decrease ◽  
X Ray ◽  
Precipitation Efficiency ◽  
Method Of Determination ◽  
Sensitivity Curves ◽  
Order Of Magnitude ◽  
Metrological Parameters

A method for determination of Cr, Fe, Co, Ni, Cu, Zn, Hg and Pb in waters by Energy Dispersive X Ray Fluorescence (EDXRF) was implemented, using a radioisotopic source of 238Pu. For previous concentration was employed a procedure including a coprecipitation step with ammonium pyrrolidinedithiocarbamate (APDC) as quelant agent, the separation of the phases by filtration, the measurement of filter by EDXRF and quantification by a thin layer absolute method. Sensitivity curves for K and L lines were obtained respectively. The sensitivity for most elements was greater by an order of magnitude in the case of measurement with a source of 238Pu instead of 109Cd, which means a considerable decrease in measurement times. The influence of the concentration in the precipitation efficiency was evaluated for each element. In all cases the recoveries are close to 100%, for this reason it can be affirmed that the method of determination of the studied elements is quantitative. Metrological parameters of the method such as trueness, precision, detection limit and uncertainty were calculated. A procedure to calculate the uncertainty of the method was elaborated; the most significant source of uncertainty for the thin layer EDXRF method is associated with the determination of instrumental sensitivities. The error associated with the determination, expressed as expanded uncertainty (in %), varied from 15.4% for low element concentrations (2.5-5 μg/L) to 5.4% for the higher concentration range (20-25 μg/L).

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