Graphite is a highly versatile electrode substrate material but the recorded voltammetric response is regularly complicated by varying degrees of adsorption of the analyte to the surface leading to voltammetry which is complex to analyse. We report how through the pre-adsorption of acetone the electro-activity of the substrate is unhindered but adsorption of an electro-active species is effectively blocked, hence the experimentalist is able to readily tailor the electrode so as to effectively switch the adsorption of the analyte 'on' or 'off'.