Facile strategy for synthesis of silver-graphene hybrid with controllable size and excellent dispersion for ultrasensitive electrochemical detection of acetamiprid

Electrochemical properties of metal-graphene hybrid depend on size and dispersion of metal nanoparticles on graphene sheets. The study reports a facile synthesis of silver-graphene hybrid with controllable size and excellent dispersion. Histidine-functionalized graphene quantum dots (His-GQDs) are firmly bound on graphene sheets of graphite oxide (GO) and then combined with Ag+ to form stable Ag/His-GQD/GO complex. Followed by heating in N-2 to produce Ag/His-GQD/G. The resulting hybrid offers well-defined three-dimensional structure, in which all Ag nanoparticles are uniformly dispersed on the surface of graphene sheets. Interestingly, the size and density of Ag nanoparticles can be effectively adjusted by varying mass ratio of His-GQD/GO or Ag+/GO. To construct on the aptasensor, aptamer of acetamiprid was connected to Ag nanoparticles via Ag-S bond in the hybrid immobilized on surface of glass carbon electrode. The architecture creates an excellent catalytic activity. The aptasensor based on Ag/His-GQD/G exhibits ultrahigh sensitivity, specificity and stability for electrochemical detection of acetamiprid. A linear relationship between the peak current of differential pulse voltammetry and logarithm value of acetamiprid concentration was obtained in the range from 1.0 x 10(-16) to 5.0 x 10( )(-12)M with a detection limit of 4.0 x 10(-17) M. The method has been successfully applied in detection of acetamiprid in tea.