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

Abstract

In this work, nanoporous gold (NPG) was prepared according to three different approaches, such as (i) anodization-electrochemical reduction (A-ECR, NPGA), (ii) dynamic hydrogen bubble template (DHBT, NPGB), and (iii) the combination of both methods (NPGA+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 NPGA+B electrode showed a large amount of surface defects and/or edges, greater electrochemical surface area (2.5 cm2), and increased roughness factor (35.4). Such outstanding features of the NPGA+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 NPGA+B compared to that of bare Au, NPGA, and NPGB, 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 NPGA+B sensor also revealed excellent selectivity towards MP detection in the presence of other interfering molecules or ions, reproducibility, and repeatability.