Electrochemical Detection Of Pesticide Residues In Aquatic Products On Graphene Based Sensing Interface

In recent years,with the continuous improvement of people's consumption level,food safety has become a public concern.Determination of pesticides in food has become even more important.Developed a simple,fast,cheap sensor has become a research hotspot.Electrochemical sensors are widely used in food safety research due to their high sensitivity,selectivity and portability.Nanomaterials have a large specific surface area,as well as better adsorption and catalytic properties and other characteristics.In electrochemical sensors,nanomaterials are good materials for electrode modification,and their excellent performance can significantly improve the detection performance of the sensor.In this paper,diuron and phoxim are used as the targets of detection,the glassy carbon electrode(GCE)is modified by graphene and metal nanoparticles,and electrochemical sensors with good performance are established.Phoxim rapid sensing method.The main contents of this paper include the following two parts:1.Electrochemical sensor based on nanomaterials to detect diuron in aquatic productsAn electrochemical sensor based on Hemin-rGO modified glassy carbon electrode(GCE)was developed for rapid detection of pollutants in water.The modified materials were characterized by SEM,UV-Vis and XPS.This was applied to the amperometric detection of the herbicidal diuron at an operating potential of-0.35 V(vs.Ag/AgCl).Under optimum conditions,the peak current was proportional to Diuron concentration in the range of 6.0-324.0 nM with a detection limit of 1.09 nM(S/N = 3).Seven replicate analyzes of the prepared electrochemical sensor to 50 nM diuron also showed a relative standard deviation of 2.3%and the electrode response decreased by 9.0%after 9 days at ambient temperature.Description of the sensor has good stability and repeatability.In addition,it can be successfully used to determine the presence of diuron in aquatic products,with reliable accuracy in practical sample applications and good application prospects.2.Electrochemical sensors based on zirconia modified nanomaterials are used for the detection of phoximIn this study,an electrochemical sensor based on zirconia nanoparticle(ZrO2)modified hemin-functionalized graphene oxide(Hemin-rGO)for the rapid determination of phoxim on glassy carbon electrode(GCE)was developed.The modified materials were characterized by SEM,UV-vis spectroscopy and XPS.The electrocatalytic activity of Hemin-rGO/ZrO2-CHIT/GCE on the reduction of phoxim was investigated by amperometric detection of the modified GCE applied to the potential of-0.20 V(vs.Ag/AgCl)for the detection of phoxim.Under optimal conditions,the peak current of cathode was proportional to the concentration of phoxim in the range of 3.0 10-6-1.5 10 4 M with a detection limit of 7.62 10-8 M(S/N = 3).Seven replicate analyzes of 5 ?M phoxim also showed a relative standard deviation of 1.7%for the electrochemical sensor prepared,and the electrode response decreased by 5.4%after 9 days at ambient temperature.Description of the sensor has good stability and repeatability.In addition,it can be successfully used to determine the presence of phoxim in aquatic products,with reliable accuracy in practical sample applications and has good application prospects.