title: Electrodeposition of reduced graphene oxide on a Pt electrode and its use as amperometric sensor in microchip electrophoresis.
abstract: This report describes the development and application of a novel graphene-modified electrode to be used as amperometric sensor in microchip electrophoresis (ME) devices. The modified electrode was achieved based on electroreduction of graphene oxide on an integrated Pt working electrode of a commercial ME device. The surface modification was characterized by SEM and cyclic voltammetry techniques. The results indicated that graphene sheets were successfully deposited exhibiting higher surface conductivity and greater electrode sensitivity. The performance of the modified electrode for the amperometric detection on ME devices has been demonstrated by the separation and detection of an anionic mixture containing iodide and ascorbate. The graphene-modified electrode provided significantly higher sensitivity (896.7 vs. 210.9 pA/μM for iodide and 217.8 vs. 127.8 pA/μM for ascorbate), better separation efficiencies (3400 vs. 700 plates/m for iodide and 10 000 vs. 2400 plates/m for ascorbate), enhanced peak resolutions (1.6 vs. 1.0), and LODs (1.5 vs. 5.3 μM for iodide and 3.1 vs. 7.3 μM for ascorbate) in comparison with the unmodified Pt electrode. The proposed amperometric sensor was successfully applied for the analysis of ascorbic acid (through its anionic form) in a commercial medicine sample, and the results achieved were in agreement with the value provided by the supplier. Based on the data here presented, the modified graphene electrode shows great promise for ME applications.
authors.affiliation: Instituto de Química, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil.
authors.forename: Bruno Gabriel
authors.initials: BG
authors.lastname: Lucca
authors.affiliation: Instituto de Química, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil.
authors.forename: Fábio
authors.initials: F
authors.lastname: de Lima
authors.affiliation: Instituto de Química, Universidade Federal de Goiás, Goiânia, GO, Brazil.
authors.forename: Wendell K T
authors.initials: WK
authors.lastname: Coltro
authors.affiliation: Instituto de Química, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil.
authors.forename: Valdir Souza
authors.initials: VS
authors.lastname: Ferreira
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D046209:Electrophoresis, Microchip / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D006108:Graphite / Q000737:chemistry*; D008956:Models, Chemical; D010984:Platinum / Q000737:chemistry*; D015203:Reproducibility of Results; D013499:Surface Properties
chemical_list: D010984:Platinum; D006108:Graphite; D001205:Ascorbic Acid
keywords: Electrochemical deposition; Electrochemical detection; Graphene; Microfluidic devices; Modified electrodes