Département de chimie moléculaire

Impedance spectroscopy transduction combined with the immunosensor technol. has been used for the detn. of atrazine, a herbicide. The sensor electrode was based on the immobilization of anti-atrazine antibody by affinity binding onto a polypyrrole film N-substituted by nitrilotriacetic acid NTA electrogenerated on a gold electrode. The poly NTA film was previously modified by the coordination of Cu2+ ions by the chelating NTA centers. The anti-atrazine antibody Fab fragment K47 modified with histidine-tag was then anchored by affinity interactions between the histidine-tag and the coordinated Cu2+. Cyclic voltammetry expts. confirm that the antibody immobilization and the resulting immunosensor were applied to the impedimetric detection of atrazine without reagent and labeling step. The immunoreaction of atrazine on the attached anti-atrazine antibody directly triggers an increase in the charge transfer resistance proportional to the atrazine concn., allowing the detection of extremely low atrazine concn., namely 10 pg/mL-1. [on SciFinder(R)]