The article compares the determination of an SPE (Screen Printed Electrodes) electrochemical active surface (AS) by the analysis of cyclic voltammogram in ferro-ferricyanide using Koutecky equation and by confocal and electron microscopy. SPE reliability is influenced by mass transport of analyte to active electrode surface while the physical properties of SPE are reproducible and stable. The electrode reaction involves the upper layer of SPE. The AS is the same as the geometrical area. Other methods set the active/geometrical area relation to 2,03 ± 0,04 (gold working electrode) and 4,35 ± 0,08 (platinum working electrode). It is demonstrated that nanostructures on working electrode surface can be efficient at high frequencies (>10 kHz). The active area of SPE determined by scanning electron microscopy or optical measurement exhibits a standard deviation lower than 2%. It proves SPE be reliable and precise electrochemical device under optimal hydrodynamic conditions.

Electrochemical measurements are generally done under isothermal conditions. Here we report on the application of a controlled temperature gradient between the working electrode surface and the solution. Using electrochemical sensors prepared on ceramic materials with extremely high specific heat conductivity, the temperature gradient between the electrode and solution was applied here as a second driving force. This application of the Soret phenomenon increases the mass transfer in the Nernst layer and enables more accurate control of the electrode response enhancement by a combination of diffusion and thermal diffusion. We have thus studied the effect of Soret phenomenon by cyclic voltammetry measurements in ferro/ferricyanide. The time dependence of sensor response disappears when applying the Soret phenomenon, and the complicated shape of the cyclic voltammogram is replaced by a simple exponential curve. We have derived the Cotrell-Soret equation describing the steady-state response with an applied temperature difference.