Electrochemical detection of methyl-paraoxon based on bifunctional cerium oxide nanozyme with catalytic activity and signal amplification effect

A new electrochemical sensor for organophosphate pesticide (methyl-paraoxon) detection based on bifunctional cerium oxide (CeO2) nanozyme is here reported for the first time. Methyl-paraoxon was degraded into p-nitrophenol by using CeO2 with phosphatase mimicking activity. The CeO2 nanozymemodified electrode was then synthesized to detect p-nitrophenol. Cyclic voltammetry was applied to investigate the electrochemical behavior of the modified electrode, which indicates that the signal enhancement effect may attribute to the coating of CeO2 nanozyme. The current research also studied and discussed the main parameters affecting the analytical signal, including accumulation potential, accumulation time, and pH. Under the optimum conditions, the present method provided a wider linear range from 0.1 to 100 mu mol/L for methyl-paraoxon with a detection limit of 0.06 mu mol/L. To validate the proof of concept, the electrochemical sensor was then successfully applied for the determination of methyl-paraoxon in three herb samples, i.e., Coix lacryma-jobi, Adenophora stricta and Semen nelumbinis. Our findings may provide new insights into the application of bifunctional nanozyme in electrochemical detection of organophosphorus pesticide. (C) 2020 Xi'an Jiaotong University. Production and hosting by Elsevier B.V.

Automated summary

This study introduces a new electrochemical sensor based on CeO2 nanozyme for detecting organophosphate pesticide. The CeO2 nanozyme-modified electrode shows a wider linear range and lower detection limit under optimized conditions.