Fig. 3. Cyclic voltammetry of NADP⁺/NADPH. (A) Diffusion-controlled, quasi-reversible interconversion of NADP⁺ and NADPH at a stationary FNR@ITO/PGE electrode, with increasing amounts of NADP⁺, scan rate 5 mV s^–1. (B) Effect of electrode rotation at scan rate 1 mV s^–1: stationary electrode with 50 μM NADP⁺ (black) and under 3000 rpm rotation with 50 μM NADP⁺ (blue) or 50 μM NADPH (red). Other conditions: buffer solution containing 25 mM MES, 25 mM TAPS, pH 8.0, 20 °C, purged with Ar before measurement.