Alteration of diffusional transport by migration and natural convection. Theoretical and direct experimental evidences upon monitoring steady-state concentration profiles at planar electrodes

Enzyme-mediator kinetics studies with SECM: Numerical results and procedures to determine kinetics constants

“…In the GC mode, the ultramicroelectrode tip of the SECM is basically used as a passive probe that could detect an electroactive metabolite (see for example [1]), and the method is similar to those used to map the diffusion-reaction profiles of electroactive species produced at a larger electrode [8] (and reference therein). In the feedback mode (FB) that is considered in this paper, the redox mediator that initiates the enzyme reaction is directly generated at the ultramicroelectrode [5].…”

Charge neutralization process of mobile species developed during potentiodynamic conditions. Part 1: Theory

“…Because of this, several electrochemical techniques have been developed to render information associated with the transference of electrons and the transport phenomena of chemical species into this zone [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Similarly, many theoretical studies have been performed to consider processes related to the movement of reactants and products into the solution as well as to the kind of reaction that occurs in the system [1,2,[16][17][18][19][20][21][22][23][24][25][26][27][28].…”

“…Similarly, many theoretical studies have been performed to consider processes related to the movement of reactants and products into the solution as well as to the kind of reaction that occurs in the system [1,2,[16][17][18][19][20][21][22][23][24][25][26][27][28]. These analyses commonly require the use of modern in situ electrochemical techniques for the measurement of such processes [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

“…One group corresponds to techniques such as FTIR, ellipsometry, electrochemical quartz crystal microbalance, surface plasmon resonance, SERS or DEMS that provide information about chemical species or reactions present at the electrode surface [1,2,[6][7][8][9]. The second group involves techniques such as spatially resolved UV-vis spectroelectrochemistry, scanning electrochemical microscopy (SECM), confocal resonance Raman microcopy, probe beam deflection (PBD) or interferometry that have been created for measuring parameters associated with the concentration of mobile species or fluxes of soluble species near the surface of an electrode or another substrate [1][2][3][4][5]7,[9][10][11][12][13][14][15]. Moreover, this group includes techniques that give information on the total concentration of electroactive or absorption species at the diffusion layer, as well as techniques that provide data on the mass fluxes (concentration gradients) in front of the electrode/solution interface [10].…”

New observation of near-reversible behaviors for the redox couple in vesicular solution

“…As we all know, the knowledge of mass transport (i.e. diffusion, migration and convection) in solution is of crucial importance in electrochemistry since it influences the nature and intensities of currents monitored at electrode [21]. The voltammetric behavior of the electroactive species in the presence and absence of supporting electrolyte is different [22].…”