Gold nanoparticles anchored marine sponge-like cobalt oxide nanocomposite for ultrasensitive electrochemical detection of arsenic

Abstract

The present study reports exceptional electrocatalytic performance of gold (Au) nanoparticles embedded within a marine sponge-like cobalt oxide (Co3O4) spinel framework for the rapid and sensitive electrochemical detection of trivalent arsenic [As(III)]. The Au@Co3O4 composite has been extensively characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) with elemental mapping, Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) to confirm phase purity, structural integrity, and successful synthesis. The electrochemical sensing property of the as synthesized composite has been evaluated by square wave anodic stripping voltammetry (SWASV) technique using a glassy carbon electrode. The sensor demonstrated an ultra-low limit of detection (LOD) of 8ppt ± 0.024ppt (S/N = 3) and high sensitivity of 0.125 μA ppb−1 cm−2, within a linear dynamic range (LDR) of 500 ppt to 10 ppb. The calibration plot followed the equation y = 2.77x – 0.7427 with a correlation coefficient (R2) of 0.9862. The limit of quantification (LOQ) was calculated to be 24.9ppt ± 0.3ppt, with a relative standard deviation (RSD) of 0.078 %. The sensor exhibited excellent durability and stability, retaining consistent current responses over 150 successive cycles, confirming its robustness and potential for practical applications in trace arsenic detection.