Amperometric Immunosensor Based on Gold Nanoparticles and Saturated Thiourea for Carbofuran Detection

A new label-free immunosensor for the determination of carbofuran was proposed in this paper. Saturated thiourea (TU) and gold nanoparticles (GNPs) were modified onto the glassy carbon electrode surface to form a GNPs/TU film, which provided an interface containing-NH₂ to assemble the second GNPs for the immobilization of anti-carbofuran antibody. Bovine serum albumin was used for blocking the non-specific adsorption sites. Thus, a novel amperometric immunosensor for carbofuran was prepared. The electrochemical properties of the modified processes were characterized by electrochemical impedance spectroscopy and cyclic voltammetry. Under the optimal conditions, the current response was proportional to the concentration of carbofuran ranging from 1.0 ng/mL to 100.0 ng/mL and from 100.0 ng/mL to 200 μg/mL with the detection limit 0.11 ng/mL. The proposed amperometric immunosensor exhibited high sensitivity, low cost and simplified procedures, which provided a new promising tool for the detection of pesticides residues in food and environment.