The switching potential is the upper limit potential and serves to: 1) over-oxidize the surface groups to increase adsorption; and/or 2) renew the electrode surface by stripping the topmost layer of carbon. These phenomena have been observed and discussed by others prior . The optimal switching potential that gave the best signal was 1.2 V. Moreover, maximal sensitivity for Trp was observed when the switching potential (or amperometric potential as referred to by Calhoun et al. ) was held for 2 ms (Figure ). Longer duration displays a scenario of diminishing returns. While having a switching potential just below the stripping limit (1.3 V) and a relatively shorter amperometric hold time yield the highest sensitivity for Trp sensing may initially seem counterintuitive, we hypothesize that these results can be explained via surface polymerization. It is possible that Trp polymerization on the carbon surface is enhancing the signal for Trp measurement. This is in accordance with work done by others 68 that demonstrated glutamate polymerization on CFMs yielding greater sensitivity of the electrode to dopamine detection compared to pre-polymerization. We believe that a similar phenomenon is occurring with Trp. This could explain why the highest sensitivity observed was for a switching potential just below stripping and also for the lowest amperometric holding duration of 2 ms.