An efficient sensor for simultaneous determination of Hg (II) and As (III) using a carbon paste electrode modified with needle-shaped Pt-doped NiCo2O4 nanograss

Abstract

The present study introduces a square wave anodic stripping voltammetry (SWASV) to detect mercury (Hg (II)) and arsenic (As (III)) in water samples exploiting a needle-shaped Pt-doped NiCo2O4/Carbon paste electrode (NS-Pt-doped NiCo2O4/CPE). The new nanocomposite was initially synthesized with a simple hydrothermal method and successfully characterized by different analyses. Before applying the SWASV, the precision and sensitivity of the developed electrode were improved by optimizing various parameters such as the electrolyte, the pH of the solution, modifier concentration, accumulation time, and deposition potential. The proposed modified electrode exhibited a great stripping voltammetric response and an excellent electron transfer activity for Hg (II) and As (III) when compared with the bare CPE. The sensor had a low limit of detection (LOD) of 0.05 and 0.09 μg/L as well as a broad linear dynamic range (0.1–125.0 μg/L) for Hg (II) and As (III), respectively. The acceptable selectivity of the proposed sensor to Hg (II) and As (III) caused slight interference with other heavy metals like Cu2+, Ag+, K+, Na+, Zn2+, Ca2+, Cd2+, Al3+ and Mg2+. The obtained results confirmed the significant applicability of the proposed method to detect Hg (II) and As (III) ions simultaneously in real water samples, validated by inductively coupled plasma mass spectrometry (ICP-MS).