scholarly journals Simulation of Alternative Differential Multi-pulse Voltammetry. Evaluation of the Electrochemical Reversibility by the Voltammogram Symmetry

2019 ◽  
Vol 92 (1) ◽  
pp. 95-102
Author(s):  
Dijana Jadreško
Keyword(s):  
Electron Transfer ◽  
Transfer Reaction ◽  
Electrode Reaction ◽  
Electron Transfer Reaction ◽  
Electrode Reactions ◽  
Electrochemical Reversibility ◽  
Kinetically Controlled ◽  
Standard Rate ◽  
Pulse Voltammetry ◽  
Standard Rate Constant

A theoretical analysis of reversible and kinetically controlled electrode reactions in conditions of alternative differential multi-pulse voltammetry (ADMPV) is presented. The degree of reversibility, as well as symmetry of the electron transfer reaction, can be estimated by visual inspection of the ADMP voltammogram. The values of electron transfer coefficient and the standard rate constant of a simple electrode reaction Ox + ne− ⇄ Red, can be determined from the slope of linear dependence of the peak currents ratio on the logarithm of pulse duration. The criteria for recognition of reversible and kinetically controlled electrode reactions by alternative differential multi-pulse voltammetry are given.

Electrochemistry and spectroelectrochemistry of bismanganese biscorroles dyads

2011 ◽  
Vol 15 (03) ◽  
pp. 188-196 ◽  
Author(s):  
Ping Chen ◽  
Maya El Ojaimi ◽  
Claude P. Gros ◽  
Jean-Michel Barbe ◽  
Roger Guilard ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Anion Radical ◽  
Transfer Reaction ◽  
Electron Transfer Reaction ◽  
Stable Form ◽  
Exact Nature ◽  
Nonaqueous Media ◽  
Face To Face ◽  
Axial Ligation ◽  
Electrode Reactions

Three manganese biscorrole dyads were synthesized, physicochemically characterized and investigated as to their electrochemistry and spectroelectrochemistry in nonaqueous media. Each dyad contained the same two corroles linked in a face-to-face arrangement via one of the three different linking groups, 9,9-dimethylxanthene, anthracene or diphenylether, the exact nature of which determined the distance and possible interaction between the two metallomacrocycles. The initial compounds contained Mn ( III ) in their air stable form and were shown to exhibit two major redox processes, one being a Mn (III)/ Mn (IV) conversion and the other being either Mn ( III )/ Mn ( II ) or reduction at the conjugated macrocycle to give a Mn ( III ) corrole π-anion radical when the solvent was pyridine. The potentials and reversibility of each electron transfer reaction were shown to depend upon the solvent (pyridine, CH2Cl2 , or PhCN ), type of spacer separating the two macrocycles and/or the presence or absence of axial ligation. The site of each electron transfer was assigned on the basis of spectroscopic and electrochemical data and by comparison with reactions and properties of the monocorrole ( Mes2PhCor)Mn which was characterized in a previous publication and also examined in the current study under the same solution conditions as the newly investigated dyads. Some electrode reactions of the dyads were followed by coupled chemical reactions and these were also elucidated in the present study.

scholarly journals Electron transfer studies of a conventional redox probe in human sweat and saliva bio-mimicking conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Krishnaveni ◽  
V. Ganesh
Keyword(s):  
Electron Transfer ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Transfer Reaction ◽  
Electron Transfer Reaction ◽  
Redox Couple ◽  
Liquid Crystalline Phase ◽  
Transfer Reactions ◽  
Redox Probe ◽  
Human Sweat

AbstractModern day hospital treatments aim at developing electrochemical biosensors for early diagnosis of diseases using unconventional human bio-fluids like sweat and saliva by monitoring the electron transfer reactions of target analytes. Such kinds of health care diagnostics primarily avoid the usage of human blood and urine samples. In this context, here we have investigated the electron transfer reaction of a well-known and commonly used redox probe namely, potassium ferro/ferri cyanide by employing artificially simulated bio-mimics of human sweat and saliva as unconventional electrolytes. Typically, electron transfer characteristics of the redox couple, [Fe(CN)6]3−/4− are investigated using electrochemical techniques like cyclic voltammetry and electrochemical impedance spectroscopy. Many different kinetic parameters are determined and compared with the conventional system. In addition, such electron transfer reactions have also been studied using a lyotropic liquid crystalline phase comprising of Triton X-100 and water in which the aqueous phase is replaced with either human sweat or saliva bio-mimics. From these studies, we find out the electron transfer reaction of [Fe(CN)6]3−/4− redox couple is completely diffusion controlled on both Au and Pt disc shaped electrodes in presence of sweat and saliva bio-mimic solutions. Moreover, the reaction is partially blocked by the presence of lyotropic liquid crystalline phase consisting of sweat and saliva bio-mimics indicating the predominant charge transfer controlled process for the redox probe. However, the rate constant values associated with the electron transfer reaction are drastically reduced in presence of liquid crystalline phase. These studies are essentially carried out to assess the effect of sweat and saliva on the electrochemistry of Fe2+/3+ redox couple.

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