AN ELECTRODE MODIFIED WITH AuNPs /GRAPHENE NANOCOMPOSITES FILM FOR THE DETERMINATION OF METHYL PARATHION RESIDUES

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 NaBH 4 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.