A novel poly rutin (Ru) modified paraffin-impregnated graphite electrode (WGE) was fabricated by electrochemical method. The field emission scanning electron microscope (FE-SEM), infrared spectra (IR), in situ UV-spectroelectrochemical and electrochemical techniques proved the immobilization of rutin on WGE. Ru undergoes electrochemical oxidation in two ways related to the two catechol hydroxyl groups and the other two hydroxyl groups; the former not only carries out a two-electron two-proton reversible reaction, but also produces unstable phenoxy radicals which readily polymerize to strongly adhere to WGE surface companying Ru monomer embeded and adsorbed in the film (Ru/WGE). The Ru/WGE displayed strong catalytic function for the oxidation of adrenalin (EP), serotonin (5-HT), and ascorbic acid (AA) and resolved the overlap voltammetric response of EP and AA into two well-defined voltammetric peaks of about 172 mV with DPV. A linear response in the range of 3.0-90.0 mu M with detection limit (s/n = 3) of 8.0 x 10(-7) M for EP was obtained in coexistence of AA (0.01 mM). (c) 2006 Published by Elsevier Ltd.