Mercury (II) sensor based on nanosilver/chitosan modified screen-printed carbon electrode

Abstract

This study introduces a highly sensitive platform for ultratrace mercury [Hg (II)] detection, utilizing a screen-printed carbon electrode (SPCE) modified with silver nanoparticles (AgNPs), chitosan (CS), and carbon nanotubes (CNTs). The AgNPs were synthesized using a green method incorporating CS and CNT hybrids, leading to their immobilization on the CNT sidewalls, resulting in nanoscale silver electrode arrays on the SPCE. Detection of Hg (II) involved the formation of Hg/Ag amalgam on the AgNPs/CS/CNT-modified SPCE surface by depositing mercury species onto elemental mercury. Hg (II) detection successfully occurred through the stripping of both Hg⁰ and Ag⁰ at a potential of +0.16 V in a supporting electrolyte (0.10 M HCl and 0.10 M KCl). This newly established detection method demonstrates exceptional selectivity and sensitivity, featuring a remarkable linear range for Hg (II) concentration from 1.0 nM to 12.6 nM, with an impressive correlation coefficient (R²) of 0.982 (n = 13) and a low detection limit of 0.4 nM. The designed electrode effectively measured Hg (II) levels in textile samples, yielding acceptable recovery results, while also exhibiting remarkable reproducibility and precision. This work presents a novel, highly sensitive, and selective approach for ultratrace Hg (II) detection, with promising applications in environmental monitoring and analytical chemistry.