title: Simultaneous/selective detection of dopamine and ascorbic acid at synthetic zeolite-modified/graphite-epoxy composite macro/quasi-microelectrodes.
abstract: The present paper aims to miniaturize a graphite-epoxy and synthetic zeolite-modified graphite-epoxy composite macroelectrode as a quasi-microelectrode aiming in vitro and also, envisaging in vivo simultaneous electrochemical detection of dopamine (DA) and ascorbic acid (AA) neurotransmitters, or DA detection in the presence of AA. The electrochemical behavior and the response of the designed materials to the presence of dopamine and ascorbic acid without any protective membranes were studied by cyclic voltammetry and constant-potential amperometry techniques. The catalytic effect towards dopamine detection was proved for the synthetic zeolite-modified graphite-epoxy composite quasi-microelectrode, allowing increasing the sensitivity and selectivity for this analyte detection, besides a possible electrostatic attraction between dopamine cation and the negative surface of the synthetic zeolite and electrostatic repulsion with ascorbic acid anion. Also, the synthetic zeolite-modified graphite-epoxy composite quasi-microelectrode gave the best electroanalytical parameters for dopamine detection using constant-potential amperometry, the most useful technique for practical applications.
authors.affiliation: Department of Applied Chemistry and Engineering of Inorganic Compounds and Environment, Politehnica University of Timisoara, Timisoara 300006, Romania. elida.ilinoiu@chim.upt.ro
authors.forename: Elida Cristina
authors.initials: EC
authors.lastname: Ilinoiu
authors.forename: Florica
authors.initials: F
authors.lastname: Manea
authors.forename: Pier Andrea
authors.initials: PA
authors.lastname: Serra
authors.forename: Rodica
authors.initials: R
authors.lastname: Pode
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis*; D004298:Dopamine / Q000032:analysis*; D055664:Electrochemical Techniques; D004852:Epoxy Compounds / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D008839:Microelectrodes; D017641:Zeolites / Q000737:chemistry*
chemical_list: D004852:Epoxy Compounds; D017641:Zeolites; D006108:Graphite; D001205:Ascorbic Acid; D004298:Dopamine