Sulfur-Doped g-C3N4/Nafion Based Electrochemical Platform for the Trace Level Detection of Pb2+

Abstract

The presence of lead Pb²⁺ in drinking water pose a significant risk to human health if its concentration exceeds permissible limits. Thus, the detection of Pb²⁺ is essential for assessing water quality and facilitating its real-time assessment. Here, S-g-C₃N₄ is synthesized via a one-pot thermal polymerization synthesis, modified with nafion (Nf) and named as S-g-C₃N₄/Nf/GCE. This modified material is employed for the selective detection of Pb²⁺ in trace levels by differential pulse anodic stripping voltammetry (DPASV). The performance of the S-g-C₃N₄/Nf/GCE electrochemical sensor is optimized for operational parameters, namely deposition potential, time, and pH of electrolyte. The electrochemical sensor showed an excellent linear response towards Pb²⁺ detection in the 5 nM–2.5 µM range. The sensor demonstrated a limit of detection (LOD) of 0.16  ±  0.004 nM and a sensitivity of 93.03 μA cm⁻² μM⁻¹. The electrochemical sensor displayed very high selectivity towards Pb²⁺ especially in the coexistence of other metal ions such as Na⁺, Ca²⁺, K⁺, Ni²⁺, Co³⁺, Cd²⁺, Cu²⁺, and Hg²⁺. The real-time effectiveness of the electrochemical sensor is validated by employing it in tap water sample.