Electrochemical immunosensor for salbutamol detection based on CS-Fe3O4-PAMAM-GNPs nanocomposites and HRP-MWCNTs-Ab bioconjugates for signal amplification

An ultrasensitive electrochemical immunosensor based on chitosan-iron oxide-poly(amino-amine) dendrimers-gold nanoparticles (CS-Fe3O4-PAMAM-GNPs) nanocomposites and horseradish peroxidase-multiwall carbon nanotubes-antibody (HRP-MWCNTs-Ab) bioconjugates was developed for the detection of salbutamol (SAL). CS-Fe3O4-PAMAM-GNPs nanocomposites as immobilization matrix were used to enhance the electroactivity and stability of the electrode. HRP-MWCNTs-Ab bioconjugates as label were used to improve catalytic activity for hydrogen reduction of the electrode. Under the optimized conditions, a calibration plot for SAL was obtained with a linear range between 0.11 ng/mL and 1061 ng/mL (r = 0.9984). The detection limit was 0.06 ng/mL. The immunosensor was examined in real samples for the analysis of SAL. (C) 2011 Elsevier B.V. All rights reserved.