Studies On Porous Graphene Modified Electrodes And Their Application In Pesticide Determination

With all kinds of pesticides are used in agricultural production widespreadly, pesticide residues have threaten human health. Therefore, it is of great significance to develop rapid, sensitive, credible and convenient detecting methods. In recent years, with the development of electrochemical technology, the electrochemical biosensors have drawn the interest of researchers because of their advantages, such as low cost, simple equipment, rapid response and high sensitivity. In this paper, according to the enzyme inhibition, the electrochemical enzyme biosensors based on the porous graphene modified electrode were prepared for the detection of carbamate pesticides. The main content includes:(1) The porous graphene was synthesized with KOH and the biosensor based on the porous graphene modified electrodes was prepared. The immobilized AChE remained relatively high bioactivity and showed high affinity to acetylthiocholine with a Michaelis-Menten (Km) constant value of 0.73 mM. The pesticide carbaryl was detected under the optimal experimental. Furthermore, based on the inhibition of the enzymatic activity caused by the model compound of carbaryl, it was found that the inhibition activity of carbaryl was proportional to its concentration ranging from 1～50 ng mL-1. The developed biosensor showed a detection limit of 0.5 ng mL-1 for carbaryl detection and exhibited good performance such as reproducibility and stability.(2) The porous graphene oxide was synthesized with HNO3 and the biosensor based on the porous graphene modified electrodes was prepared. The pesticide carbaryl was detected under the optimal experimental. The Km was 1.75 mM and the inhibition activity of carbaryl is proportional to its concentration ranging from 10～70 ng mL-1 with a correlation coefficient of 0.997. The developed biosensor shows a detection limit of 5 ng mL-1 for carbaryl.(3) The biosensor based on the three-dimensional mesoporous graphene modified electrodes was prepared. The pesticide carbaryl was detected under the optimal experimental. The Km was 1.45 mM and the inhibition activity of carbaryl is proportional to its concentration ranging from 100～500 ng mL-1 with a correlation coefficient of 0.998. The developed biosensor shows a detection limit of 50 ng mL-1 for carbaryl.