Supporting Information Delayed voltammetric with respect to amperometric electrochemical detection of concentration changes in microchannels

Obtaining the peak current ip from raw CV data The raw CV data obtained during the experiments featured two characteristics, which could potentially complicate the data analysis. First, because of the relatively high scan rate (10 V s) used for these experiments, the background current was quite important and could potentially hinder the determination of the concentration profiles from the voltammetric data. Additionally, minute variations in the first voltage sweeps of the acquisition, due to electrode discharge or stabilization, could introduce further inaccuracies. For these reasons, CV measurements were performed in the background buffer (PBS) and were substracted from the raw data (Figure S1). This background substraction method is routinely used for the processing of fast-scan CV data. From the resulting signal, the peak currents ip could be identified, and the time variations of these currents was analyzed and plotted on graphs, such as the ones presented in the main text.