The Study For Electron Transfer Mechanism Of Neurotransmitter Dopamine, 5-Hydroxytryptamine And Co-exist Molecule Ascorbic Acid

ABSTRACTThe radical condition for maintaining the normal function and behaviorof life is the communication linking between cells. The neurotransmitter is thecarrier of these cornrnunications. The investigation on the neurotransmitter isimportant because it can provide useful insights into many life phenomena.For the complexity of the life process, it is difficult to study the whole courseof info-transferring in electrochemistry. But electrospectrochemistry, whichcombines electrochemistry and spectroscopy, has proved to be an effectiveteclmology for studying the redox mechanism of biomolecules. Using thismethod, the signals of electrochemistry and spectroscopy can be gained at thesame time. We have done some work on the neurotransmitter and the in-vivodisturbance ascorbic acid. The main results are expressed as follows'l. The reduction mechanism of ascorbic acid at platinum electrode wasstudied detailedly by spectroelectrochemistry and electrochemistrytechnologies respectively. A pair of new redox peaks has been fOund at Ptelectrode in negative potential, Which is a quasi-reversible redox reaction witha one-electron transfer process. The intermediate of tertiary carbon freeradical exists in this process. The reaction rates constant and the diffosioncoefficient was acquired. A possible reaction mechanism has been proposed.2. The Dopamine reaction mechanism on GC electrode surface wasstudied detailedly by electrochemistry and Spectroelectrochemistry techniques.The results indicate that the electro-oxidation of Dopamine is a one-electrontransfer process other than a two-electron transfer process reported byliteratures. The intermediate of O-semiquinone free radical exists in thisprocess. Cyclic voltammetry shows a quasi-reversible process by cyclicpotelltial scanning between -0. I V and 0.6V The saturated adsorption amouflt,reaction rate constaflt ks were investigated by single-step chronocoulometryIIelectrospectrochemistry and electrochemistry respectively.3. The electro-reaction of 5-Hydroxytryptamine on GC electrode surfacewas studied by electrochemistry and electrospectrochemistry techniques. Theresults indicate that the redox of 5-Hydroxytryptamine is a quasi-reversibleelectro-reaction under the colltrol of diffusion. Tryptamine-4,5-dione, the4-electron oxide, was found by the signal of spectroscopy. By calculating thedata of electrochemistry and electrospectrochemistry the oxides of l electronand 2 electron transferring were discovered, so that a possible reactionmechanism was proposed and the amount of all oxides was worked out.