Acetylcholinesterase sensors based on gold electrodes modified with dendrimer and polyaniline - A comparative research

Potentiometric and amperometric enzyme sensors based on modified gold electrodes have been developed and compared in pesticide determination. PAMAM dendrimer (generation G4) stabilized with 1-hexadecanethiol was used for the immobilization of acetylcholinesterase from electric eel and choline oxidase from Alcaligenes species in the assembly of amperometric sensor. Polyaniline-doped with camphorsulfonic acid was used to obtain potentiometric response. Trichlorfon, carbofuran and eserine suppress the biosensor response due to their inhibitory effect. The detection limits of 0.003 and 200 nmol l(-1) (trichlorfon), 0.04 and 6 nmol l(-1) (carbofuran) and 0.1 and 700 nmol l(-1) were obtained for amperometric and potentiometric sensors, respectively. The difference in the biosensor behavior and the high sensitivity of the dendrimer modified sensor to the inhibitors is due to the specific organization of protein layer at charged surface of the modifier macromolecules. (C) 2004 Elsevier B.V. All rights reserved.