Preparation And Application Of Graphene Doped Poly Amino Acid Modified Electrode

Graphene doped poly(amino acid) modified electrode(PAA-ERGO/GCE) was prepared on the carbon glassy electrode, the electrochemical behavior of levodopa(LDA),p-acetamidophenol(ACOP), p-aminophenol(PAP), ascorbic acid(AA) and rutin(Rt) were studied by cyclic voltammetry and differential pulse voltammetry, and some electrochemical behavior including the adsorption and diffusion characteristics were studied on the modified electrode. New methods for the above all kinds of material individually and simultaneously determining were developed. With adding graphene during the electrochemical polymerization of amino acid, the catalytic ability of the surface of modified electrode was enhanced, which further improved the determination sensitivity and declined the detection limit of determination materials. In comparation with bare glassy carbon electrode,PLP-ERGO/GCE could significantly decrease electrochemical impedance and accelerate the electron transfer. The PLP-ERGO/GCE electrode was of high sensitivity and selectivity, and had been successfully applied to determine LDA, ACOP, PAP, AA and Rt in samples. The modified electrodes were used to determination of samples with satisfactory results.The major problems to be solved in working process are as fellows:(1) Preparation conditions of PLP-ERGO/GCE and investigation of catalytic ability and electrochemical impedance;(2) to study the preparations and characterizations of the graphene doped poly(L-arginine) modified electrode;(3) to discuss the electrochemical behavior of LDA, ACOP,PAP;(4) to discuss the optimal conditions of LDA, ACOP, PAP, established the measurement method.(5) to discuss the electrochemical behavior of AA and Rt, a new method of simultaneous determination of AA and Rt.The main works and the detail achievements were exhibited as follows:1. The graphene doped poly L-phenylalanine modified glassy carbon electrode(PLP-ERGO/GCE) was prepared by electropolymerization method(Cyclic voltammetry). The voltammetric behavior for levodopa(LDA) was studied on that electrode and a determination method was set up. In p H 2.0 phosphate buffer solution and at a scan rate of 0.05V/s,PLP-ERGO/GCE gave a sensitive oxidation peak at 0.478 V(vs. Ag/Ag Cl). The linear response was obtained in the range of 7.50×10-6~2.50×10-4 mol/L. The detection limit was7.5×10-7 mol/L. The method was successfully applied to the determination of LDA in sample with satisfactory results.2. The graphene doped poly L-phenylalanine modified glassy carbon electrode(PLP-ERGO/GCE) was prepared by electropolymerization method(Cyclic voltammetry). The voltammetric behavior for p-acetamidophenol(ACOP) was studied on that electrode and a determination method was set up. In p H 2.5 phosphate buffer solution and at a scan rate of0.10V/s, PLP-ERGO/GCE gave a sensitive oxidation peak at 0.610 V(vs. Ag/Ag Cl). The linear response was obtained in the range of 5.00×10-7~2.50×10-4 mol/L. The detection limit was 1.0×10-7 mol/L. The method was successfully applied to the determination of ACOP in sample with satisfactory results.3. The graphene doped poly L-phenylalanine modified glassy carbon electrode(PLP-ERGO/GCE) was prepared by electropolymerization method(Cyclic voltammetry). The voltammetric behavior for p-aminophenol(PAP) was studied on that electrode and a determination method was set up. In p H 3.0 phosphate buffer solution and at a scan rate of0.10V/s, PLP-ERGO/GCE gave a pair of redox peaks at Epa=0.462 V, Epc=0.363 V for PAP(vs. Ag/Ag Cl). The linear response was obtained in the range of 2.50×10-6~5.00×10-4 mol/L.The detection limit was 1.0×10-6 mol/L. The method was successfully applied to the determination of PAP in sample with satisfactory results.4. PLA-GO/GCE was applied to study electrochemical behavior of rutin and ascorbic acid(AA). A new method of simultaneous determination of rutin and ascorbic acid was established in the basis of optimum onditions. In p H 2.0 phosphate buffer solution at a scan rate of 0.05 V/s, two sensitive oxidation peaks at 0.605 V for rutin and 0.273 V for AA(vs. Ag/Ag Cl) were presented respectively. Besides, a reduction peak at 0.552 V for rutin was gave at PLA-GO/GCE. The two oxidation peaks of rutin and AA could be separated by 0.332 V. The determination linear range for rutin and AA were 3.00×10-7 ~ 2.00×10-5 mol/L and 5.00×10-6~ 5.00×10-3 mol/L, respective. The detection limit were 3.0×10-6 and 1.0×10-7 mol/L. The method was successfully applied to the determination of AA and Rt in sample with satisfactory results.