Effects of thin-layer diffusion in the electrochemical detection of nicotine on basal plane pyrolytic graphite (BPPG) electrodes modified with layers of multi-walled carbon nanotubes (MWCNT-BPPG)

The oxidative electrochemistry of nicotine is measured in aqueous solution at a multi-walled carbon nanotube modified basal plane pyrolytic graphite (MWCNT-BPPG) electrode. Quantitative detection of nicotine is obtained with a limit of detection of 1.5 μM (based on 3σ) and a linear range of at least up to 1 mM. Evidence is found for a mass transport regime that includes thin-layer (within the MWCNT layers) as well as semi-infinite (from bulk solution) diffusional signatures, adding to the growing picture that the fundamental source of the ‘electrocatalytic’ properties claimed of many porous and multi-walled carbon nanotube-based modified electrodes may, at least in some cases, be due to mass transport effects rather than electronic or structural peculiarities of the modifying layers.