Figure 3

(A) DPASV of 15 μg L⁻¹ of Cd²⁺ and Pb²⁺ on (a) GCE, (b) Bi/GCE, (c) Nafion/GCE, (d) (N, S-G)-Nafion/GCE and (e) Bi/(N, S-G)-Nafion/GCE. (B) DPASV of simultaneous analysis of Pb²⁺ and Cd²⁺ with concentrations of 30, 24, 18, 15, 12 and 9 μg L⁻¹, respectively. (C) The calibration curve of Cd²⁺ and Pb²⁺, respectively. Supporting electrolyte: 0.2 M acetate buffer (pH 4.6), deposition potential: −1.2 V, deposition time: 300 s. (D) DPASV of 15 μg L⁻¹ of Cd²⁺ and Pb²⁺ on rGO-Nafion/GCE, Bi/(S-G)-Nafion/GCE, Bi/(N-G)-Nafion/GCE and Bi/(N, S-G)-Nafion/GCE (from bottom to upper).