title: Highly selective determination of dopamine in the presence of ascorbic acid and serotonin at glassy carbon electrodes modified with carbon nanotubes dispersed in polyethylenimine.
abstract: We report the highly selective and sensitive voltammetric dopamine quantification in the presence of ascorbic acid and serotonin by using glassy carbon electrodes modified with a dispersion of multi-wall carbon nanotubes (MWCNT) in polyethylenimine, PEI (GCE/MWCNT-PEI). The electrocatalytic activity of the MWCNT deposited on the glassy carbon electrode has allowed an important decrease in the overvoltages for the oxidation of ascorbic acid and dopamine, making possible a clear definition of dopamine, serotonin and ascorbic acid oxidation processes. The sensitivities for dopamine in the presence and absence of 1.0 mM ascorbic acid and serotonin were (2.18 +/- 0.03) x 10(5) microAM(-1) (r = 0.9998); and (2.10 +/- 0.07) x 10(5) miroAM(-1) (r=0.9985), respectively, demonstrating the excellent performance of the GCE/MWCNT-PEI. The detection limit for dopamine in the mixture was 9.2 x 10(-7) M. The R. S. D. for the determination of 50 microM dopamine using four different electrodes was 3.9% when modified with the same MWCNT/PEI dispersion, and 4.6% when using four different dispersions. The modified electrode has been successfully applied for recovery assays of dopamine in human blood serum. Therefore, the new sensor represents an interesting and promising alternative for the electrochemical quantification of neurotransmitters and other analytes of clinical interest.
authors.affiliation: INFIQC, Departamento de Físico Química, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Marcela C
authors.initials: MC
authors.lastname: Rodríguez
authors.forename: María D
authors.initials: MD
authors.lastname: Rubianes
authors.forename: Gustavo A
authors.initials: GA
authors.lastname: Rivas
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D003102:Colloids / Q000737:chemistry; D003460:Crystallization / Q000379:methods; D004298:Dopamine / Q000032:analysis*; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005898:Glass / Q000737:chemistry; D008422:Materials Testing; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods; D008839:Microelectrodes; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D011094:Polyethyleneimine / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012701:Serotonin / Q000032:analysis*
chemical_list: D003102:Colloids; D037742:Nanotubes, Carbon; D012701:Serotonin; D011094:Polyethyleneimine; D001205:Ascorbic Acid; D004298:Dopamine