A new-doped method based on electrochemical polymerization of aniline in the presence of ferrocene perchlorate and perchloric acid was presented. Polyanilines (PAn and PAnFc) were polymerized in the solution of perchloric acid and the solution containing ferrocene perchlorate and perchloric acid, respectively. Both flame atomic absorption spectrometry and infrared spectrum indicated that ferrocene perchlorate was assured to be doped into the polyaniline. We presumed that ferrocene perchlorate was combined via electrostatic adsorption onto the chain of polyaniline. The effect of pH on the electrochemical characteristics of PAn and PAnFc was studied by cycle voltammetry. Compared with PAn prepared in the absence of ferrocene perchlorate has a rather high electrochemical activity at pH > 4. The electrochemical oxidation of ascorbic acid (AA) on both PAn film and PAnFc film modified Pt electrode was also performed. The results indicated that the catalytic activity of the PAnFc film to AA was better than that of the PAn film. The anodic peak currents of AA (measured by constant potential amperometry) increased linearly with the concentration of AA in the range of 8.0 x 10(-5)-1.0 x 10(-2) mol/L. The detection limit (S/N = 3) obtained was 1.0 x 10(-5) Mol/ L. (c) 2006 Wiley Periodicals, Inc.