Voltammetric selectivity conferred by the modification of electrodes using conductive porous layers or films: The oxidation of dopamine on glassy carbon electrodes modified with multiwalled carbon nanotubes

Amperometric detection provides a highly sensitive approach to the electroanalytical determination of many target molecules and is widely used in the laboratory and field as well as in the form of disposable sensors. However, the approach can occasionally be restricted by limitations of selectivity: various species present in the target medium may oxidise or reduce at similar potentials. We show that the use of conducting porous layers on the surface of electrodes can be used to modify the mass transport regime from linear (planar) diffusion to one of approximately 'thin layer' character and that this alteration can in favourable circumstances facilitate the amperometric discrimination between species which oxidise or reduce at similar potentials under planar diffusion conditions.