Figure 3. (A) Effect of pH on the cyclic voltammograms recorded for a 5.0 104 mol L1 concentration solution of GA at a scan rate of 50 mV s1. pH values: 2.0, 3.0, 5.0, and 7.0. Reference electrode = Ag/AgCl. (B) Plot of Ipa versus pH. (C) Plot of Epc versus pH; solid line corresponds to a slope of 61 mV per unit of pH.