Ultrasensitive detection of kanamycin in animal derived foods by label-free electrochemical immunosensor

A label-free amperometric immunosensor based on graphene sheet(GS)-nafion(Nf)/thionine(TH)/Pt nanoparticles modified electrode is proposed for the ultrasensitive detection of kanamycin. The anti-kanamycin antibody was immobilised onto the GS-Nf/TH/Pt modified glassy carbon electrode (GCE) through electrostatic adsorption. TH was selected as an electron transfer mediator, and the synergistic effects among GS, TH and Pt were investigated. The electroactivity of TH was greatly improved in the presence of GS and Pt due to their good electron-transfer ability. The proposed immunosensor shows good performance such as low detection limit (5.74 pg/mL), wide linear range (from 0.01 to 12.0 ng/mL), high stability, and good selectivity in the detection of kanamycin. The reliability of the developed immunosensor was proved by determination of kanamycin in animal derived foods with satisfactory results. (C) 2012 Elsevier Ltd. All rights reserved.