Screen-printing technology is widely used for the mass-production of disposable electrochemical sensors. The practical utility of carbon screen-printed electrodes has been exploited, despite the fact that little is known about the nature of the electrode reactions. (Wang, J.; Pedrero, M.; Sakslumd, H.; Hammerich, O.; Pingarron, J. Electrochemical activation of screenprinted carbon strips. The Analyst 1996, 121 (3), 345-350). Given the complexity of carbon electrodes in general, and differences in the composition of commercial carbon inks, the question arises as to how such differences and complexity affect their electrochemical reactivity. The aim of this work was to compare the electroactivity of both commercial electrodes and electrodes fabricated in-house from various commercial inks, in order to find the electrode most suited to amperometric sensor work. Methods of analysis include cyclic voltammetry, amperometry and linear sweep voltammetry. It was found that the commercial working electrodes were not suited to the high current work of interest, due to their poor charge transfer properties. The in-house electrode had less resistive properties, and was more suited for high current amperometric sensing. Utilizing this electrode configuration, an optimal carbon paste was chosen for the working electrode.