Figure 2.

(A, B) Schematic diagram of the fabrication of the G/MWCNTs/GCE sensor, differential pulse anodic stripping voltammetry (DPASV) stripping signals for Zn²⁺, Cd²⁺, Pb²⁺, and Cu²⁺ ions on the sensor. (Adapted with permission from [59], © (2014) Elsevier). (C) Summary of the fabrication of the Bi/C SPE sensor and the square wave anodic stripping voltammetry (SWASV) signals recorded for Pb²⁺ and Cd²⁺. (Adapted with permission from [65], © (2016) Springer). (D) Summary of the fabrication of the DNA modified Fe₃O₄@Au NPs and MGCE sensor and the procedure for the simultaneous detection of Ag⁺ and Hg²⁺. (Adapted with permission from [70], © (2017) American Chemical Society).