Amino Acid Chemically Modified Glassy Carbon Electrode Surface Charge Nature Of The Study

Chemically modified electrodes is very active in the electrochemistry and electroanalytical chemistry fields. A covalent modified glassy carbon electrode with L-Glutamic or L-Tyrosine or L-Lysine has been fabricated via an electrochemical oxidation procedure. The one-electron oxidation of the amino group turns into its analogous cation radical through electrochemical oxidation. 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 to form three kinds of amino Chemically modified electrodes.Took Fe(CN)₆^3-/4- as an electroactive redox probe combining cyclic voltammetry to investigate the assembly state and surface charge character of three kinds of amino monolayer and then research the forms and the transformation of surface charge character among three kinds of amino monolayer. It could be conclude below.1.Three kinds of amino monolayer can link to the carbon surface and form a little compact monolayer.The electron exchange of electrode and redox center in the solution is mostly the active material diffuse to surface of the electrode via the pinhole defection of the film.2.In neutral condition, three kinds of amino monolayer show electronegative,which has an electrostatic repulsion to the negative redox probe.3.The surface charge character of three kinds of amino modified electrodes will vary with the change of environment. With the increase of pH in solution., the electronegative density of amino modified electrodes will increasing, the electrostatic repulsion to the negative redox probe will increase.With the increase of Ca²⁺ concentration in solution, the electrostatic repulsion to the negative redox probe will decrease.4.The capacity's size ranking of electric double layer among amino modified electrodes and solution's interface is L-Tyrosine modified electrodes-solution interface> L-Glutamic modified electrodes-solution interface > L-Lysine modified electrodes- solution interface5.The L-Glutamic molecules assemblied on the glassy carbon electrode can react with Cu²⁺ in the solution to form a complex compound.6. The stability of three kinds of amino monolayer is good. After the modified electrodes are ultrasomic cleaned in the ultrapure water or ethanol or cyclic scanned in PBS,they all show good stability.