A novel architecture was designed by controllable electrodeposition of silver nanoparticles doped chitosan hydrogel film for electrochemical sensing of trichloroacetic acid. The as prepared hydrogel film presents excellent ability to facilitate the diffusion and electron transfer process of the negatively charged redox couple [Fe(CN)(6)](3-)/[Fe(CN)(6)](4-) benefitting from positively charged chitosan in acidic solutions. Based on this, by combining the excellent electrocatalytic properties toward trichloroacetic acid, a sensitive amperometric sensor for trichloroacetic acid is constructed with a low detection limit. (C) 2012 Elsevier Ltd. All rights reserved.