Figure 4.

Cyclic voltammograms (A–C) and differential pulse voltammograms (D–I) registered for 1.4 mM celosianin, argentianin, and amaranthin in various buffers at pH 3 (A, D), pH 5 (B, E), and pH 7 (C, F), as well as the influence of pH on the anodic oxidation of Cel (G), Arg (H), and Am (I), respectively. pH dependence of the DPV oxidation potentials Epa^I and Epa^II for Cel (G, J), Arg (H, K), and Am (I, L), as well as the pH dependence of anodic current Ipa^I and Ipa^II Cel (M), Arg (N), and Am (O). CV voltammograms were recorded at a scan rate of 25 mV/s.