Voltammetry for quantitative determination of trace mercury ions in water via acetylene black modified carbon paste electrode

Abstract

A sensitive acetylene black modified carbon paste electrode was fabricated for the determination of trace mercury ions in water samples. Nitric acid treatment of acetylene black (TAB) produced a porous structure with large surface area and defects, improving its performance as an electrode modifier. Under optimized conditions, the TAB/CPE showed good selectivity and sensitivity towards mercury ions. The peak current exhibited a linear relationship with mercury ion concentration from 10 nM to 0.1 mM, with a detection limit of 8.8 nM. The enhanced sensitivity results from a synergistic effect between the properties of TAB and carbon paste. The porous structure, large surface area and defects in TAB improve mercury ion adsorption and electron transfer kinetics. Meanwhile, the carbon paste provides a stable and conductive electrode base. The developed sensor showed good stability, repeatability and reproducibility, as well as acceptable recovery results when applied to detect mercury ions in simulated water samples. This simple and rapid electrochemical method holds potential for the determination of trace mercury ions in environmental water samples.