The indirect electrochemical detection and quantification of DNA through its co-adsorption with anthraquinone monosulphonate on graphitic and multi-walled carbon nanotube screen printed electrodes

The voltammetric responses arising from the co-adsorption of anthraquinone monosulfonate and DNA on to a graphitic electrode are reported. The electrochemical responses of these two species show that the adsorbed species are non-interacting and further they occupy similar sites upon the electrode surface. Consequently it is demonstrated that there is an inverse linear relationship between the surface concentrations of the two species, such that it is possible to indirectly measure the quantity of adsorbed DNA to the electrode through the voltammetric signal of the co-adsorbed anthraquinone monosulfonate. This system is developed through the use of multiwalled carbon nanotube screen-printed electrodes to provide a proof-of-concept analytical methodology via which it is possible to accurately analyse the concentration of a DNA solution, where the limit of detection is shown to be 8.8 μM (equivalent to 5.9 μg/mL).