(A) CVs of ERGO/GCE in PBS containing 1.0×10−5 M of rutin with different pH values (2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0). (a) Plot of peaks currents of rutin (Ip) vs pH. (b) The linear relationship between the anodic peaks potentials and pH. (B) CVs of 1.0×10−5 M rutin on ERGO/GCE with different scan rates (20, 40, 100, 200, 300, 400, 500, 600, 700, 800, 900 mV/s, respectively) in PBS. Inset shows linear relationship between scan rates (v) and redox peaks currents (Ip). (C) Linear relationship between the redox peaks potentials (Ep) and lgv. (D) The relationship between accumulation time (t) and peaks currents (Ip).