Preparation And Analyticalapplication Of Uranyl Ion Imprinted Electrochemical Sensor

Uranium is one of the essential radionuclides,it can be employed as fuel for nuclear power plants,military industry and for electron microscopy studies of biological samples.As these applications may be harmful to mankind’s health or the environmental protection of uranium mines,it is essential to rapidly and accurately detect trace uranyl ions in environmental,geochemical or clinical samples.Although traditional detection methods interest from high sensitivity and favorable detection limits,their application demands costly equipment and lofty operating expenses.Therefore,in this paper a novel imprinted electrochemical sensor was constructed to detect uranyl ions in the environment.The magnetic imprinting sensor developed also laid the foundation for the detection of other metal ions.（1）Based on the surface of magnetic ion imprinted membrane（MIIP）with the high selectivity and differential pulse voltammetry（DPV）detection of high sensitivity,the study developed an MIIP magnetic carbon paste electrode（MIIP/MCPE）sensor for the admeasurement of uranyl ions in sophisticated matrices.Density functional theory（DFT）was employed to investigate the interaction between templates and monomers to screen out suitable functional monomers for the reasonable design of the ion imprinted sensors.The MIIP/MCPE modified with Fe₃O₄@Si O₂exhibited strong response current and high sensitivity toward uranyl ion comparison with the bare carbon paste electrodes.Meanwhile,the magnetic electrode of neodymium iron boron（MCPE）was fabricated simultaneously under the action of strong magnetic adsorption,and the ion imprinted membrane can be adsorbed stably on the electrode surface,handing the problem that the imprinted membrane is easy to fall off during the process of experimental detection and elution.Based on the uranyl ion imprinting network,differential pulse voltammetry（DPV）was adopted for the detection technology to realize the electrochemical reduction of uranyl ions,which improved the selectivity of the sensor.Thereafter,the linear range of uranyl ions detection by the ion imprinted sensors is 0.5μg/L～100μg/L,and the detection limit is 0.16μg/L（S/N=3）.In addition,the sensor has also been successfully demonstrated for the determination of uranyl ions in uranium tailings soil samples and water samples with a recovery of96.29%～103.22%.（2）A novel electrochemical sensor combined with carbon nanomaterial-graphene was developed for the determination of trace uranyl ions.Firstly,the uranyl ligand H₄L was synthesized with the monomers 3-aminopropyltrimethoxysilane（APTMS）and ethyl orthosilicate（TEOS）by hydrolyzing and polymerizing to obtain a polymer sol-gel.The sol-gel was used as a receptor for selective combing and sensing of uranyl ions in aqueous solutions.The performance of the sensor was tested using differential pulse voltammetry.It was illustrated that the ion-imprinted polymer sol-gel modified carbon paste electrodes were selective for uranyl ions compared to electrode containing non-ion-imprinted polymer sol-gel.The ion-imprinted sensor was established with a good linear relationship from 5.02μg/L～1.5×10³μg/L with a lower detection limit was 0.66μg/L（S/N=3）.The sensor has also been successfully applying for sensing uranyl ions in actual uranium tailings soil and water samples.