The Construction And Preliminary Application Of Glutamic Acid Electrochemical Sensor

Glutamate(Glu)is an important substance in protein synthesis,which provides energy and substances for plant growth,promotes the development of plant organs,and plays an important role in plant growth.Quantitative analysis and detection of Glu is helpful to study the transduction pathway and physiological process of Glu in the process of nitrogen metabolism in plants,and has important application value in agriculture,medicine,food and other fields.Compared with fluorescence analysis,high performance liquid chromatography,microdialysis,capillary electrophoresis and other detection methods,electrochemical sensor method has the characteristics of simple operation,easy to carry,fast response and high sensitivity,which has attracted extensive attention of researchers.In this thesis,a disposable screen-printed electrode(SPE)was first used to realize the specific detection of Glu by modifying glutamate oxidase.Secondly,an interdigital electrode(IDES)was used to amplify the detection signal of Glu by depositing gold/platinum nanoparticles to improve the conductivity of the electrode to prepare a Glu enzyme-free electrochemical sensor.The specific research results are as follows:1.Construction of a new glutamate oxidase electrochemical sensor based on a gold-platinum nanoparticle functionalized graphene/carbon nanotube platformGold/Platinum nanoparticles(Au/Pt NPs)are deposited on the surface of SPE by electrodeposition to increase electrode conductivity,and then graphene(GR)/carbon nanotubes(MWNT)are dripped onto EDC/NHS for carboxylation to generate amides Better bond fixation of glutamate oxidase(Gluta Ox)to achieve specific detection of Glu.Due to the specific recognition of Glu by Gluta Ox,the sensor has shown good performance in the actual application process,and tested with different concentrations of glutamic acid under different p H values(3.5-7.5).The test results show that the sensor It has a lower limit of detection(LOD)of 0.35 ?M(S/N=3)and a wide detection range: 2 ?M ?16 m M.The recovery rate was tested in tomato juice and a better recovery rate(99.38% ? 108.7%).Finally,the tomato was tested in vivo,which proved that the glutamic acid electrochemical sensor has strong practical value.2.Glutamate enzyme-free electrochemical sensor based on Au-Platinum/nanoparticle modificationGold/platinum nanoparticles(Au/Pt NPs)are deposited on the surface of IDES by electrodeposition to increase electrode conductivity,reduce the reaction voltage of Glu in actual detection,increase the catalytic oxidation of Glu,and realize the detection of Glu.Under the optimal experimental conditions,the detection range of the sensor is500 n M-3 m M,and the LOD is 220 n M(S/N=3).It also shows good performance in terms of selectivity,sensitivity and reproducibility.The sensor has passed the recovery test in sodium glutamate(MSG),and has obtained a good recovery rate(97.70% ?101.71%).It shows that the sensor has a good prospect in practical application.