Fabrication of dendritic nanoporous gold via a two-step amperometric approach: Application for electrochemical detection of methyl parathion in river water samples

In this work, nanoporous gold (NPG) was prepared according to three different approaches, such as (i) anodization-electrochemical reduction (A-ECR, NPG(A)), (ii) dynamic hydrogen bubble template (DHBT, NPG(B)), and (iii) the combination of both methods (NPG(A+B)). Field-emission scanning electron microscopy (FE-SEM) and cyclic voltammetry (CV) were used to investigate the structural morphology and the electrochemical behavior of the fabricated materials. The NPG(A+B) electrode showed a large amount of surface defects and/or edges, greater electrochemical surface area (2.5 cm(2)), and increased roughness factor (35.4). Such outstanding features of the NPG(A+B) platform were demonstrated by the sensitive detection of methyl parathion (MP) in river water samples. CV results indicated nearly 25-fold, 6-fold, and 2.5-fold higher sensitivity for NPG(A+B) compared to that of bare Au, NPG(A), and NPG(B), respectively. Differential pulse voltammetry (DPV) results show a linear behavior in the MP concentration range of 5-50 ng mL(-1) with a limit of detection (LOD) of 0.6 ng mL(-1) and limit of quantification (LOQ) of 2.0 ng mL(-1). Besides, the NPG(A+B) sensor also revealed excellent selectivity towards MP detection in the presence of other interfering molecules or ions, reproducibility, and repeatability. (AU)