Preparation And Electrochemical Properties Of Lysine Monolayer Glassy Carbon Electrode

Molecule assembly is one of the active and promising fields in the chemistry of material and analytical chemistry especially in electro analytical chemistry fields. A covalent modified glassy carbon electrode with Lysine has been fabricated via an electrochemical oxidation procedure. The electrostatic interaction and assembly state of the monolayer has been investigated by electrochemical cyclic voltammetry and AC impedance. The experiment results indicated that there is a not very compact Lysine monolayer on the surface of glassy carbon electrode, which has an electrostatic repulsion to the negative redox probe. It has potential application in improving the blood compatibility of biomedical materials to make the surface of carbon electrode has an electrostatic repulsion to negative matters through electrochemical oxidation.The main experiment content and result are as following:1. The one-electron oxidation of the amino group turns into its analogous cation radical through electrochemical oxidation in nonaqueous medium (anhydrous ethanol solution, 0.1M LiClO4). These cation radicals form a chemically stable covalent linkage between the nitrogen atom of the amine and the edge plane sites at the carbon electrode surface.2. Took Fe(CN)6~3-/4- as an electroactive redox probe to investigate the electrochemical behavior and stability of Lysine monolayer. All the results show that Lysine molecule link to the carbon surface through its terminal amino group and from a compact monolayer. Because of the existence of the monolayer, the electrode has an electrostatic repulsion to the negative redox probe, furthermore the electrostatic repulsion increase with the increase of pH in solution, and decrease with the increase of Ca+. After long time storage, being sonicated in water and anhydrous ethanol, respectively and repetitious scanning in buffer solution, the stability of the Lysine-GCE system was tested. The stability of Lysine monolayer is good.3. AC impedance is combined to analyze the assembly state of the monolayer. Calculating the coverage of Lysine monolayer on the surface of carbon glasselectrode.