Simultaneous Detection of Cd+2, Pb2+, and As+3 Ions in Water Using Green-Synthesized Gold Nanoparticles by Square Wave Anodic Stripping Voltammetry

Gold nanoparticles (AuNPs) were synthesized by phytosynthesis using the leaf extracts of Azadirachta Indica (neem) and Hibiscus Rosasinesis (hibiscus) and hydrogen chloroaurate followed by characterization using transmission electron microscopy (TEM), Fourier transform infrared (FTIR), UV–visible spectroscopy (UV–Vis), and X-ray diffraction. AuNPs formed from hibiscus leaf extract (HLE) were more stable compared to that from neem leaf extract (NLE). Electrochemical sensing of heavy metal ions was carried out successfully using hibiscus-synthesized AuNPs (H-AuNPs) modified glassy carbon electrode (GCE). Optimization of pH, deposition time (DT), and deposition potential (DP) was carried out for individual and simultaneous detection of Cd
$^{+2}$
, Pb
$^{+2}$
, and As
$^{+3}$
by square wave anodic stripping voltammetry (SWASV). Selectivity and interference studies were carried out. Real water sample of the Mahanadi River was tested for the presence of Cd
$^{+2}$
, Pb
$^{2+}$
, and As
$^{+3}\,\,\vphantom {_{\int }}$
by SWASV. The limit of detection (LOD) of Cd
$^{+2}$
, Pb
$^{2+}$
, and As
$^{+3}$
ions in water using H-AuNPs was 8.59, 1.85, and 4.77 nM, respectively, when detected individually. For simultaneous detection, the LOD for Cd
$^{+2}$
, Pb
$^{\mathbf {2+}}$
, and As
$^{+3}$
ions was 11.92, 23.72, and 77.48 nM, respectively. Mahanadi River water was analyzed and 0.6 nM of Cd
$^{+2}$
was detected.