Copper-Labeled Voltammetric Immunosensor for Carbaryl Detection

Abstract

A hapten-protein conjugate for determining carbaryl using copper nanoparticles was first synthesized in the present work. The copper nanoparticles were used as electrochemical labels in the direct solid-phase competitive analysis of carbaryl residues in flour from some crops. Copper nanoparticles stabilized by chitosan and a hapten-protein conjugate with copper nanoparticles stabilized by chitosan by UV/VIS - spectroscopy, transmission electron microscopy, and dynamic light scattering are characterized. To form a recognition receptor layer of monoclonal antibodies against the carbaryl on the surface of a gold-graphite electrode, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, dicyclohexylcarbodiimide and 1-hydroxy-2,5-pyrrolidinedione were found to be the best covalent cross-linkers. When selection the electrochemical immunosensor conditions, working dilutions of the antibodies and the hapten-protein conjugate with copper nanoparticles copper nanoparticles stabilized by chitosan were selected to detect the carbaryl. The effect of ethyl alcohol on the performance of the electrochemical immunosensor for the determination of carbaryl was evaluated. The specificity of the developed electrochemical immunosensor was investigated by testing structurally related carbaryl compounds; the results did not exceed 7%. The electrochemical immunosensor can be used for highly sensitive determination of carbaryl residues in flour samples with a detection limit of 0.08 μg /kg within a range of detectable contents of 0.8-32.3 μg/kg.