Preparation And Application Of Isopro-Turon Electrochemical Sensors

Isoproturon(IPU),as a substituted urea herbicide,has been widely used to control grass weeds and most broadleaf weeds such as wheat,corn,soybeans and other crops.The group of urea is its core structure.IPU could interfere the photosynthesis electron transport in target weeds.Due to its water-solubility,adsorption-priority,leaching-convenience,the residue of IPU is hard to degrade in sandy soils.Recently,it is increasing concentrated to the pesticides management in many countries,such as the United States,the European Union and so on.Considering that amounts of backwards in classical analytical methods,it is super necessary to develop a convenient,specific and time-consuming methods to detect the residue of pesticide with high sensitivity.Carbon nano-tubes become popular with their brilliant electrical properties and stable structures.Currently,Au nanoparticles was increasingly applied in electrochemical sensors,for improving the sensitivity of detection.In this paper,an adsorption material was prepared using acid(MAA)and ethylene glycol dimethacrylate(EGDMA)and the process was optimized.The experimental conditions were also optimized.In addition,the electrochemical sensors were used for the determination of isoproturon in water and soil.Details are as follows:1.Preparation,characterization and adsorption capacity of the adsorption material.The adsorption material was synthesized by adding methacrylic acid(MAA),ethylene glycol di-methacrylate(EGDMA),azobisisobutyronitrile(AIBN)and toluene into a flask.Scanning electron microscopy(SEM)was used to characterize the adsorption material.To study the adsorption capacity of the material,isothermal adsorption was performed.The results showed that the adsorption capacity increased with the increasing of isoproturon concentration and reached the maximum at 0.3 mmol·L-1.2.Preparation,characterization of the modified electrode and detection of isoproturon.First,the MWCNTs suspension was coated on electrode surface to obtain the MWCNTs/GCE electrode.Then the electrode was immersed in a certain concentration of HAuCl4,and cyclic voltammetry(CV)was used to obtain Au/MWCNTs/GCE electrode.Scanning electron microscopy(SEM),cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)were used to characterize the different modified electrodes.Experimental results showed that the Au/MWCNTs/GCE could accelerate electron transfer,and reduce the resistance.3.The concentrations of isoproturon were detected under the most optimal conditions using the proposed electrochemical sensor,in which Au/MWCNTs/GCE was applied as the working electrode.The results showed that the electrochemical biosensor had a linear relationship with the concentration of 10-100 nmol · L-1.Under he spiked concentration of 15,50 and 85 nmol · L-1 IPU,the average recoveries were the range of 101.29-95.7%and 115.83-89.35%,respectively.