Figure 2

(a) Differential pulse voltammetry curves of 100.0 µM L-tryptophan on graphite electrode in Britton–Robinson buffer solution at different pH values, scan rate 50.0 mV/s (curves subjected to baseline correction); (b) Dependence of the peak potential of 100.0 µM L-tryptophan on pH value of the Britton–Robinson buffer solution; (c) Dependence of current peak of 100.0 µM L-tryptophan on pH value of the Britton–Robinson buffer solution.