▎ 摘　　要

Direct electrochemiluminescence (ECL) from peroxydisulfate (S2O82-), a common ECL co-reactants, can be efficiently enhanced by nanocomposite of electrochemically reduced graphene oxide (abbreviated ERGO) and gold nanoparticles, which provided a novel sensing strategy for bio-molecules. The nano-Au-ERGO composites were electrochemically prepared by a two-step reduction method, in which graphene oxide (GO) was firstly reduced to graphene at the electrode surface, and then followed by electrochemical reduction of HAuCl4. As 15 times enhanced ECL intensity of (S2O82-) was observed with the formation of nanocomposite at glassy carbon electrode (GCE) and immunoreaction occurred at electrode surface can suppress corresponding ECL emissions, a new immunoassay strategy was developed with Human IgG (HIgG) as model molecule. A leaner response from 0.02 to 100 ng mL(-1) was obtained between the concentration of the target molecular and ECL intensity with a detection limit of 1.3 pg mL(-1) (S/N = 3). The proposed ECL sensor showed high sensitivity, stability and satisfactory reproducibility and opened a new avenue to apply ECL in more biological assays. Besides, this method is economical, efficient, and potentially attractive for clinical immunoassays. (C) 2012 Elsevier B.V. All rights reserved.