Graphene nanoplatelets are shown to electrocatalyse the oxidation of dopamine. Single entity measurements (‘nano-impacts’) coupled with microdisc voltammetry and UV-visible spectroscopy reveal that adsorption of dopamine and its oxidised product on the graphene nanoplatelets is the key factor causing the observed catalysis. Genetic implications are drawn both for the study of catalysts in general and for graphene nanoplatelets in particular.</p