The electrosynthesis of polyaniline (PAN!) film has been achieved on glassy carbon electrode (GCE) in a novel ionic liquid medium by means of cyclic voltammetry (CV) Then a copper nanoparticles (Cu-NPs) film was in situ electrochemically deposited on the surface of PANI/GCE Electrochemical behavior and surface characteristics of the Cu-NPs/PANI/GCE were studied using cyclic voltammetry scanning electron microscopy (SEM) and the results confirmed the presence of PANI and Cu-NPs on the electrode surface Cu-NPs were highly dispersed and firmly stabilized by surface attachment of the PANI which was prepared in ionic liquid and strongly attached to the electrode surface The Cu NPs/PANI/GCE showed excellent electrocatalytic activity toward the oxidation of ascorbic acid (AA) under weakly basic conditions Amperometry was carried out to determine the concentration of AA at 0 2 V and a good linear concentration range from 0 005 to 3 5 mM was found The Cu-NPs/PANI composite film on GCE surface showed good reproducibility and stability 2010 Elsevier B V All rights reserved