Sensors Graphene Modified Electrode Based Multicomponent Determination Of Biomolecules

This research mainly using graphene modified electrodes, in order to develop akind of biosensor which is used for multicomponent detection. The paper provides akind of modified electrodes method which has some advantages: simple operation,good reproducibility, and low cost. In addition, break the traditional synthesismenthod of graphene, use the electrochemical reduction of graphene oxidegraphene. It is a green, environmental protection method. And this modifiedelectrode can be used for simultaneously detection of AA, UA and DA. This thesismainly includes the following aspects of content:1Electrochemical behavior researchof Hemoglobin immobilized on graphene modified electrodes.Hemoglobin (Hb)immobilized on graphene modified electrodes is applied in this article, and we havestudied the electrochemical properties of modified electrode. First of all, we getgraphene modified electrodes by electrochemical reduction method, then usemolecular self-assembly method modified Hb, obtaining Hb/ERGO/GC modifiedelectrode. Then electrochemical behavior of Hb/ERGO/GC modified electrode wasinvestigated using cyclic voltammetry. The results show that quasireversible electrontransfer reaction takes place between electrode and Hb. In addition, the cyclicvoltammograms of the buffer solution of oxygen saturation test results show that themodified electrode presents favourable catalytic effect for reduction of oxygen. Theexperiment results show that in view of modified electrodes, graphene can changeelectron transfer process in glassy carbon electrode.2Simultaneously detection of AAand UA by graphene modified electrodes.By electrochemically reduced grapheneoxide (ERGO) which was adsorbed on the poly-L-lysine (PLL) modified glassy carbonelectrode by immersed in grapheme oxide (GO) solution for4h, then GO wasreduction by electrochemical, ERGO/PLL/GC modified electrode was prepared.Electrochemical behavior of ascorbic acid (AA) and uric acid (UA) on the modifiedelectrodes was reserched, the results show that under the affection of graphene，AAoxidation peak potential is negative shift, and the oxidation of UA peak potentialalmost no change. Diffenece between of AA and UA oxidation peak potential is250 mV. The modifiled electrode as the working electrode, using differential pulsevoltammetry examines the simultaneous determination of AA and UA. The resultsshow that, with a liner ranger of0.8-3.0mmol/L for AA,25~162.5?mol/L for UA.3Simultaneously detection of AA and DA by graphene modified electrodes.On thebasis of modified electrodes. Polydimethyl-diallylammonium chloride (PDDA) wasdropped to the modified electrodes surface. Electrochemical behavior of thePDDA/ERGO/PLL/GC modified electrodes in ascorbic acid and dopamine solutionhave been investigated. The results showed that oxidation peek potential of ascorbicacid (AA) and dopamine (DA) have shifted negatively (the oxidation peek potentialdifference reached about140mV due to the action of PDDA and graphene. Thesimultaneous determination of AA and DA have done with differential pulsevoltammetry, with a linear range of0.2~2mmol/L for AA,1~230?mol/L for DA. Thismodified electrode has a good stability and repeatability.4Graphene modifiedelectrodes for the selective detection of DA when AA and UA exists.Theelectrochemical behavior of the PDDA/ERGO/PLL/GC modified electrodes in AA, DAand UA solution have been investigated. Under PDDA and graphene affection,differences among the three detected peaks were140mV (AA to DA),120mV (DA toUA), respectively. It establishs theoretical basis for selective detect DA. The selectivedetection DA have done with differential pulse voltammetry, with a linear range of5-50?mol/L，50-190??mol/L. This modified electrode has a good stability andrepeatability.