Sensitive electrochemical sensor of tryptophan based on Ag@C core-shell nanocomposite modified glassy carbon electrode

Abstract

We here reported a simple electrochemical method for the detection of tryptophan (Trp) based on the Ag@C modified glassy carbon (Ag@C/GC) electrode. The Ag@C core-shell structured nanoparticles were synthesized using one-pot hydrothermal method and characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier transform-infrared spectroscopy (FTIR). The electrochemical behaviors of Trp on Ag@C/GC electrode were investigated and exhibited a direct electrochemical process. The favorable electrochemical properties of Ag@C/GC electrode were attributed to the synergistic effect of the Ag core and carbon shell. The carbon shell cannot only protect Ag core but also contribute to the enhanced substrate accessibility and Trp-substrate interactions, while nano-Ag core can display good electrocatalytic activity to Trp at the same time. Under the optimum experimental conditions the oxidation peak current was linearly dependent on the Trp concentration in the range of 1.0×10(-7) to 1.0×10(-4) M with a detection limit of 4.0×10(-8) M (S/N=3). In addition, the proposed electrode was applied for the determination of Trp concentration in real samples and satisfactory results were obtained. The technique offers enhanced sensitivity and may trigger the possibilities of the Ag@C nanocomposite towards diverse applications in biosensor and electroanalysis.