The direct voltammetry of aqueous colloidal graphene oxide (GO) solutions is presented in this fundamental
study. Since its inception, themajority of GOelectrochemistry has been centred on the use of solid-state modified
electrodes whereas the voltammetry of solution-based GO species is notwell known. Overall, pH and GO particle
size are found to be important aspects that influence the observed results, and voltammetric profiles of nanosized
GOunder acidic condition bear the closest similarities to electrode surface-modifiedGO.Greater knowledge
of colloidal GO electrochemistry potentially allows for its future development in electrochemical sensing
applications.