Development of spherical bismuth nanoparticles modified electrode for analysis of heavy metal ions in seawater samples using SWASV technique

Abstract

This research aims to optimize the effectiveness of a glassy carbon electrode by coating it with bismuth nanoparticles in both sphere and rod forms. The modified electrode is intended for the simultaneous analysis of heavy metals: Zn(II), Cd(II), and Pb(II) by using square-wave anodic stripping voltammetry (SWASV). The synthesis optimization of bismuth nanospheres and nanorods was studied. Analysis of the nanoparticles’ morphology and structure was conducted using a scanning electron microscope (SEM). Under optimal conditions, the synthesized nanobismuth spheres measured 137.0±3.43 nm, while the bismuth rods measured 5.18±1.36 nm. The optimal SWASV conditions for the proposed electrode in heavy metal analysis involved a deposition potential of −1.4 V for 240 seconds, a frequency of 25 Hz, an amplitude of 25 mV, and a step potential of 4 mV. The linearity ranges for Zn(II), Cd(II), and Pb(II) were 20–130 μg L⁻¹, 10–60 μg L⁻¹, and 6–54 μg L⁻¹, respectively, with detection limits of 4.0 μg L⁻¹ for Zn(II), 1.6 μg L⁻¹ for Cd(II), and 1.6 μg L⁻¹ for Pb(II). The results demonstrated satisfactory performance with high repeatability, good selectivity, and sensitivity. Additionally, the proposed electrode was utilized to simultaneously determine heavy metal concentrations in seawater.