Fabrication of DNA/poly l-methionine-silver nanoparticles/pencil graphite electrode and its application to the determination of carboxin

Abstract

In this study, a novel electrochemical biosensor is reported for carboxin detection based on the fabrication of the deoxyribonucleic acid/poly l -methionine-silver nanoparticles/pencil graphite electrode (DNA/PMT-AgNPs/PGE). The electrochemical response of carboxin on the DNA/PMT-AgNPs/PGE was measured using adsorptive differential pulse voltammetry (AdDPV). The electrochemical impedance spectroscopy studies showed lower R ct values for PMT-AgNPs/PGE and DNA/PMT-AgNPs/PGE compared to PGE, demonstrating their good conductivity and faster electron transfer rate. Also, the interaction of DNA with carboxin led to the better accumulation of carboxin on the electrode surface. The proposed biosensor afforded excellent selectivity for carboxin against other pesticides. According to the findings, the DNA/PMT-AgNPs/PGE presents a linear response over the carboxin concentration ranges from 8.0\xa0pM to 1.0\xa0µM. The detection limit was obtained as 5.0\xa0pM under the optimized conditions. The applied DNA/PMT-AgNPs/PGE could successfully detect carboxin in the tap and river water.