Preparation And Application Of γ-amino-butyric Acid Selective Electrode Modified With ZnO Nanoparticles

ObjectiveVariation in concentrations of gamma-aminobutyric acid in the human body will cause some diseases associated with them, in order to identify, prevent and treat these diseases, the content determination of gamma-aminobutyric acid has very important significance in animal and plant. Germinated brown rice is the most studied in substances riching in gamma-aminobutyric acid at present. Based on the characteristics of nanometer materials, this paper for the first time get the selective electrode modified with ZnO nanoparticles, to determine the content of gamma-aminobutyric acid in brown rice and the reseults obtained agree with those of spectrophotometer determination. This method can be used for detecting and identifying the content of gamma-aminobutyric acid in one kind of brown rice to determine the nutritious value.MethodsA new all solid carbon paste electrodes, solid-state coating carbon polyvinyl chloride membrance selective electrode, solid-state coated wire polyvinyl chloride membrance selective electrode and PVC film selective electrode was prepared by using the stable association complex of o-phenanthroline-iron complex ion with y-aminobutyric acid as an electroactive substance, Afterwords, the electroactive substance was modified with ZnO nanoparticles, producing all solid carbon paste electrodes, solid-state coating carbon polyvinyl chloride membrance selective electrode, solid-state coated wire polyvinyl chloride membrance selective electrode and PVC film selective electrode. The content of y-aminobutyric acid in brown rice was quantitatively determined based on the Nernst response of the electrode to γ-aminobutyric acid.ResultThe best ordinary y-aminobutyric acid selective electrode of performance was all solid carbon paste electrode, the electrode showed Nernst response to y-aminobutyric acid in the range of1.0×10-5-8.0×10-2mol/L with a slope of38mV/pC. The detection limit was5.2×10-6mol/L.The second-best electrode was solid-state coated wire polyvinyl chloride membrance selective electrode, the electrode showed Nernst response to y-aminobutyric acid in the range of1.0×10-6～2.1×10-2mol/L with a slope of29mV/pC. The detection limit was8.6x10-7mol/L.The best y-aminobutyric acid selective electrode modified with ZnO nanoparticles of performance was solid-state coated wire polyvinyl chloride membrance selective electrode, the electrode showed Nernst response to y-aminobutyric acid in the range of8.9x10-7-1.0×10-1mol/L with a slope of61mV/pC. The detection limit was6.2x10-7mol/L. The second-best electrode was all solid carbon paste electrode, the electrode showed Nernst response to y-aminobutyric acid in the range of6.6x10-6～1.0×10-1mol/L with a slope of55mV/pC. The detection limit was2.1x10-6mol/L. The electrode can be used to determine the concentration of y-aminobutyric acid in the brown rice, the results get from detection were in conformity with spectrophotometer determination.ConclusionCompared to gamma-aminobutyric acid selective electrode modified with ZnO nanoparticles and ordinary gamma-aminobutyric acid selective electrode, the linear response range, detection limit, and response time were enhanced, and the content determination of gamma-aminobutyric acid in brown rice was more accurate, it’s applicative to the determination of actual samples. The ZnO nanoparticles added in the electroactive substance enhanced the performance of the electrodes, and laid the foundation for the further study of gamma-amino-butyric acid electrode in future.