Narrow Results

A novel sensitive and elective electrochemical sensor was developed to detect methyl parathion (MP) based on a glassy carbon electrode (GCE) modified with gold nanoparticles (AuNPs)/graphene nanocomposites film. The AuNPs were modified onto graphene sheets using NaBH₄ as a reductant. The obtained AuNPs/graphene nanocomposites were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical behavior of MP and interference studies were then investigated. Compared with metal ions and nitroaromatic compounds, which exist in environmental samples, the AuNPs/graphene/GCE exhibited high adsorption and strong affinity toward MP. Under optimized conditions, the oxidation peak current of MP was linear to its concentration within the range of 4.0 × 10^-7–8.0 × 10^-5 M, with a detection limit (S/N = 3) of 8.5 × 10^-8 M. These results indicated that the AuNPs/graphene nanocomposites displayed a synergic effect involving the catalytic characteristics of graphene and AuNPs nanocomposites, which can effectively improve the electrochemical properties of MP. Furthermore, the AuNPs also enhanced sensor sensitivity to MP. Therefore, the AuNPs/graphene/GCE could be a promising sensor for the fast, sensitive and selective detection of MP in real samples.

In this research, a new electrochemical sensor based on hybrid nanocomposite consisting of copper nanowires (CuNWs) and graphene (GR) were developed for the detection of organophosphorus pesticides (OPs). The surface morphology of the hybrid nanocomposite were studied by scanning electron microscope (SEM). The electrochemical behavior of the hybrid nanocomposites based sensor and its application for pesticides determination were evaluated by cyclic voltammetry (CV) and square wave voltammetry (SWV). Under optimized operational conditions, SWV was further employed for methyl parathion detection, which shows a wide dynamic range from $0.2\mu \mathrm{\text{M}}$ to $5\mu \mathrm{\text{M}}$, a high sensitivity ($69.2\cdot {\mathrm{\text{cm}}}^{-2}\cdot \mu {\text{M}}^{-1}$) and the detection limit as low as 50nM. It also had specific detection to the methyl parathion residues and had good reproducibility and stability. These results implicated the potential applicability of CuNWs/GNs-Chit hybrid nanocomposites in sensitive and selective detection of organophosphorus pesticides.