Direct Electroanalysis Of Electro-active Compound By Layered Double Hydroxide Film Modified Electrode

Layered double hydroxides (LDHs), also known as anionic clays or hydrotalcite-like compounds, are a class of inorganic materials with potential applications in wide areas. LDH possess special structure and excellent properties, so layered double hydroxides have been a hotspot in the area of international material subject and chemistry in last ten years. In this paper, several modified electrodes were fabricated based on the especial properties of layered double hydroxides, and successfully applied to investigate the electrochemical behavior to iodine, epinerine, uric acid, and dopamine. On this condition, methods for determination of those species were developed. The focus of this paper has been listed as follows:(1) Zn-Al LDHs were fabricated by using hydrothermal technology, the obtained productions was characterized by XRD, FT-IR and SEM. In the following, Zn-Al LDHs was spread on the surface of Au electrode in order to construct Zn-Al LDH/Au modified electrode. Making use of adsorbability and taking positive charge of LDHs, direct electroanalysis of iodine were achieved in the neuter phosphate buffer solution. The results showed that the reduction peak currents of iodine increased remarkably at the Zn-Al LDH modified Au electrode, compared with that at a bare GCE. Base on this, a fast and simple electrochemical analytical method was proposed to determine iodine.(2) Zn-Al LDHs film were electrodeposited on the glassy carbon electrode, the film was uniform and stable. At the same time, the properties of the surface of modified electrode were investigated in details. The film modified electrodes exhibit excellent electrochemical behavior to epinephrine and uric acid, moreover, it can eliminate interference of some biology molecule. Besides, the modified electrode possesses the properties of low-cost , high selectivity, excellent reproducibility and long term stability, it become an powerful instrument to diagnose epinerine and uric acid in physic field.(3) A modified electrode was construct based on graphene and layered double hydroxide on glassy carbon electrode. Considering good electrical conductivity of graphene, it can enhance the conductivity of layered double hydroxides. The effect of the quality proportion of graphene and LDH on electron-transfer resistance of the electrode was studied carefully. In the neuter phosphate buffer solution, the electrochemical behavior to dopamine was investigated, the influence of pH and scan rate were also reviewed. At the optimal condition, such electrodes successfully detect dopamine. The results suggested that in the presence of AA (0.1mM), the electrodes provide a fast and a sensitive response to dopamine between 1μM and 199μM, with the detection limit of 0.3μM. Furthermore, the modified electrode has been satisfactorily used for the determination of DA in pharmaceutical injections.