Determination of Cd²⁺ and Pb²⁺ Based on Mesoporous Carbon Nitride/Self-Doped Polyaniline Nanofibers and Square Wave Anodic Stripping Voltammetry

The fabrication and evaluation of a glassy carbon electrode (GCE) modified with self-doped polyaniline nanofibers (SPAN)/mesoporous carbon nitride (MCN) and bismuth for simultaneous determination of trace Cd²⁺ and Pb²⁺ by square wave anodic stripping voltammetry (SWASV) are presented here. The morphology properties of SPAN and MCN were characterized by transmission electron microscopy (TEM), and the electrochemical properties of the fabricated electrode were characterized by cyclic voltammetry (CV). Experimental parameters, such as deposition time, pulse potential, step potential, bismuth concentration and NaCl concentration, were optimized. Under the optimum conditions, the fabricated electrode exhibited linear calibration curves ranging from 5 to 80 nM for Cd²⁺ and Pb²⁺. The limits of detection (LOD) were 0.7 nM for Cd²⁺ and 0.2 nM for Pb²⁺ (S/N = 3). Additionally, the repeatability, reproducibility, anti-interference ability and application were also investigated, and the proposed electrode exhibited excellent performance. The proposed method could be extended for other heavy metal determination.