Enhancement of electrogenerated chemiluminescence of luminol by ascorbic acid at gold nanoparticle/graphene modified glassy carbon electrode

• Gold nanoparticles/graphene composite modified electrode is prepared.
• Luminol exhibits excellent electrogenerated chemiluminescence (ECL) at the modified electrode.
• Ascorbic acid could greatly enhance luminol ECL at the modified electrode.
• Ascorbic acid could be sensitively detected based on its enhancing effect on luminol ECL.

Gold nanoparticle/graphene (GNP/GR) nanocomposite was one-pot synthesized from water soluble graphene and HAuCl4 by hydrothermal method and characterized by TEM, Raman spectroscopy, XRD, XPS, UV–vis spectroscopy, and electrochemical impedance spectroscopy (EIS). Electrogenerated chemiluminescence (ECL) of luminol was investigated at the GNP/GR modified glassy carbon electrode (GNP/GR/GCE) and the GNP modified glassy carbon electrode (GNP/GCE) in aqueous solution respectively. The results revealed that one strong anodic ECL peak could be observed at ∼0.8 V at two modified electrodes compared with that at the bare electrode. The intensity of the anodic ECL at the GNP/GR/GCE is weaker than that at the GNP/GCE, which should be due to the synergic effect of the enhancing effect of gold nanoparticles and the inhibiting effect of graphene on anodic luminol ECL. One strong cathodic ECL peak located at ∼−0.8 V could be observed at the GNP/GR/GCE but not at the GNP/GCE, which should be result from the adsorbed oxygen at the graphene film. In the presence of ascorbic acid, the anodic ECL at the GNP/GR/GCE was enhanced more than 8-times, which is more apparent than that at the GNP/GCE. Whereas, the cathodic ECL peak was seriously inhibited at the GNP/GR/GCE. The enhanced ECL intensity at the GNP/GR/GCE varied linearly with the logarithm of ascorbic acid concentration in the range of 1.0 × 10−8 to 1.0 × 10−6 mol L−1 with a detection limit of 1.0 × 10−9 mol L−1. The possible ECL mechanism was also discussed.

Gold nanoparticle (GNP) and gold nanoparticle/graphene (GNP/GR) modified electrodes were prepared. GNP/GR could enhance anodic luminol ECL slightly and enhance cathodic luminol ECL significantly. Ascorbic acid could be detected sensitively at the GNP/GR/GCE based on its enhancing effect of anodic luminol ECL.Figure optionsDownload as PowerPoint slide