Comparative research on two kinds of amperometric immunosensor for detection of carbofuran residues

In this study, two kinds of novel label-free amperometric immunosensor for the direct detection of carbofuran was developed using layer-by-layer assembly and sol-gel technology, respectively. In one hand anti-carbofuran monoclonal antibodies were immobilized on the gold electrode (GE) surface which was modified with multilayers of L-cysteinewas, gold nanoparticles (nano-Au) and horseradish peroxidase (HRP) through layer-by-layer assembly technology, in the other hand, anti-carbofuran monoclonal antibodies were immobilized on the surface of the glassy carbon electrode (GCE) based on sol-gel technology to prepare non-labeled electrochemical immunosensor for the detection of carbofuran. The conformational properties of the immunosensor were characterized using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and a current response curve. Effects of experimental variables, such as concentration of antibody solution, pH of working buffer and incubation time, were studied in detail for optimization of analytical performance. Under optimal conditions, the current response was proportional to the concentration of carbofuran.