Figure 9.

(A) Cyclic voltammograms recorded at 100 mV s⁻¹ on a glassy carbon electrode in phosphate buffer marennine solutions (1 mg mL⁻¹) at different pH. (B) Plot of the formal potential vs. solution pH. (C) Cyclic voltammograms recorded on a glassy carbon electrode in a phosphate buffer solution (pH 3) containing marennine (1 mg mL⁻¹) at different scan rates: (a) 50 mV s⁻¹, (b) 100 mV s⁻¹, (c) 200 mV s⁻¹, (d) 300 mV s⁻¹, (e) 400 mV s⁻¹, (f) 500 mV s⁻¹, (g) 600 mV s⁻¹, (h) 700 mV s⁻¹, (i) 800 mV s⁻¹, (j) 900 mV s⁻¹, and (k) 1000 mV s⁻¹. (D) Plot of the anodic current peak intensity vs. the square root of the scan rate.