Fig. 4. Shown here are the cyclic voltammograms (bottom panel) of the PG|Cu(DAT) disk rotated at 2000 rpm taken in an oxygen-saturated (a) 0.03 M MES buffer (pH 5.2) in 0.1 M NaClO4 and (b) 0.1 M NaOH (pH 13) solution. In the graphs, the 1st (dark grey line) and 100th scan (black line) of the CV of the disk taken at a 100 mV s–1 scan rate are shown. The light grey line depicts the current response of an unmodified PG disk electrode. In addition, the current response of the platinum ring, which was held at a potential of 1.2 V, is shown in the top panel.
