Ultrahigh sensitivity electroanalysis of trace As(III) in water and human serum via gold nanoparticles uniformly anchored to Co3O4 porous microsheets

The construction of ultrahighly sensitive electrochemical sensing interfaces is essential for the accurate determination of trace-level arsenic(III) (As(III)) due to its severe toxicity. In this report, an ultrahighly sensitive electrochemical sensor was constructed for the electroanalysis of As(III) by the uniform assembly of gold nanoparticles on porous cobaltosic oxide (Co 3 O 4 ) microsheets (AuNPs/Co 3 O 4 nanocomposites). The developed sensor-modified screen-printed carbon electrode (SPCE) detected As(III) by using square wave anodic stripping voltammetry (SWASV) with an ultrahigh sensitivity of 12.1 ± 0.2 µA ppb −1 and a low limit of detection (LOD) of 0.09 ppb (S/ N  = 3). The strong electrochemical performance is attributed to the high adsorption capacity of porous Co 3 O 4 microsheets and the favorable electrocatalysis of in situ AuNPs toward As(III) reduction. In addition, the proposed method demonstrates satisfactory anti-interference performance in the presence of other metal ions (Cu(II), Pb(II), Cd(II), Zn(II), Hg(II), Ca(II), Fe(III), Mg(II), Mn(II), and Ni(II)). Robust stability and reproducibility were also realized. Most importantly, the electrochemical sensor was successfully applied to the electroanalysis of As(III) in water and human serum samples. The results of this study provide new insights into the design of sensitive and stable electrochemical sensing interfaces for the accurate analysis of trace levels of As(III) in practical applications.