On the origin of the differences between stearic-acid-modified carbon paste electrode performances after exposure to surfactant and brain tissues

Stearic-acid-modified carbon paste electrodes (StCPEs) were investigated by cyclic voltammetry and chronoamperometry, as a function of paste composition, before and after treatment by surfactant and brain tissues. It was found that the amount and viscosity of the carbon paste binding agent were important parameters, which may explain the differences in the literature data on ascorbic acid (AA) and dopamine (DA) resolution at StCPEs. The ionic strength of the investigated media was also shown to affect the voltammetric discrimination between AA and DA. The use of solid paraffin for StCPE preparation was shown to offer significant advantages in terms of robustness and voltammetric performance.