Electrochemical sensor for amino acids based on gold nanoparticles/macroporous carbon composites modified glassy carbon electrode

Gold nanoparticles/macroporous carbon (GNPs–MPC) composites were simply fabricated by electrodepositing GNPs film on MPC using cyclic voltammetry (CV). The prepared composites were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectra (XPS) and X-ray diffraction (XRD). Glassy carbon electrode (GCE) modified with GNPs–MPC was used as electrochemical sensor of l-tryptophane (l-Trp) and l-tyrosine (l-Tyr) for the first time. In 0.1 M PBS (pH = 7.4), the GNPs–MPC/GCE exhibited satisfactory electrocatalytic activity by significantly decreasing the oxidation potentials and increasing the peak currents of the oxidation of l-Trp and l-Tyr when compared with those modified electrodes. More importantly, the present electrode gave a wide linear range from 1.0 × 10−5 M to 1.0 × 10−3 M, 5.0 × 10−6 M to 1.0 × 10−3 M, a very low detection limit of 2.4 × 10−8 M, 7.4 × 10−8 M and a high sensitivity of 41 μA mM−1, 13 μA mM−1 for l-Trp and l-Tyr, respectively. Moreover, the electrode displayed a good reproducibility, a long-term stability and a favorable ability of anti-interference to electroactive-molecules.