title: Fabrication of Co3O4 nanoparticles-decorated graphene composite for determination of L-tryptophan.
abstract: A novel Co(3)O(4) nanoparticles-decorated graphene (GR) composite was synthesized by electro-deposition and characterized by scanning electron micrographs, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. Then, amperometric biosensors based on a Co(3)O(4) nanoparticles-decorated GR composite modified glassy carbon electrode (GCE) were developed for the sensitive determination of L-tryptophan (Trp). The direct electrooxidation behaviors of Trp on the Co(3)O(4)/GR/Nafion/GCE were carefully investigated by cyclic voltammetry and square wave voltammetry. The results indicated that Trp showed an increase of the oxidation peak current with a negative shift of the oxidation peak potential compared with that on the bare GCE. Under optimum conditions, the proposed biosensor can be applied to the quantification analysis of Trp with a wide linear range covering 0.05-10 μM (R = 0.996) and a low detection limit of 0.01 μM. The experimental results also showed that the sensor exhibited good reproducibility, long-term stability as well as high selectivity. Moreover, the novel biosensor for the detection of Trp in a real amino acid sample with satisfactory results has been proved.
authors.affiliation: Department of Chemistry, Shanghai University, Shanghai 200444, PR China.
authors.forename: Daixin
authors.initials: D
authors.lastname: Ye
authors.forename: Liqiang
authors.initials: L
authors.lastname: Luo
authors.forename: Yaping
authors.initials: Y
authors.lastname: Ding
authors.forename: Bingdi
authors.initials: B
authors.lastname: Liu
authors.forename: Xiao
authors.initials: X
authors.lastname: Liu
mesh_terms: D002021:Buffers; D002138:Calibration; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D058266:Dielectric Spectroscopy; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D005465:Fluorocarbon Polymers / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053761:Nanocomposites / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D055672:Static Electricity; D013499:Surface Properties; D014364:Tryptophan / Q000032:analysis* / Q000737:chemistry*
chemical_list: D002021:Buffers; D005465:Fluorocarbon Polymers; D010087:Oxides; C040402:perfluorosulfonic acid; D003035:Cobalt; D006108:Graphite; D014364:Tryptophan; C060728:cobalt oxide