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The aim of this study was to prepare three types of multiwall carbon nanotubes (CNT)-based composite electrodes and to modify their surface by copper electrodeposition for nonenzymatic oxidation and determination of glucose from aqueous solution. Copper-decorated multiwall carbon nanotubes composite electrode (Cu/CNT-epoxy) exhibited the highest sensitivity to glucose determination.

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.

Natural and synthetic zeolites were used to modify synthetic graphite based composite microelectrodes envisaging their use for simultaneous/selective detection of ascorbic acid (AA) and dopamine (DA) in aqueous solutions. Both natural and synthetic zeolite-modified synthetic graphite composite microelectrodes (ZN-GEC and SZ-GEC) were obtained in epoxy matrices, and the optimum composition was selected based on the electrochemical behavior. The composite electrodes were characterized electrochemically by cyclic voltammetry (CV) using the classical ferrycianide/ferrocyanide system method, in comparison with bare graphite composite microelectrode (GEC). The electrochemical oxidation of AA occurred at all three microelectrodes and the slowest kinetics was noticed for SZ-GEC, due to the synthetic zeolite presence with certain peculiarities in relation to the selectivity and the catalytic effect, while ZN-GEC and GEC microelectrodes exhibited very good sensitivity for AA detection in aqueous solution. Taking into consideration the fact that DA and AA coexist in real extracellular brain fluid and the fact that SZ-GEC microelectrode did not exhibited a good sensitivity towards AA detection, but a very good sensitivity for DA was obtained, makes this composite material a good

The aim of this study was to investigate photocatalytic activity of a silver doped TiO 2 modified zeolite (Z-TiO 2 -Ag) in the photocatalytic degradation of Reactive Yellow 125 (RY 125) azo dye. The operational conditions using photocatalyst dose of 1g·L -1 at pH 6 were established as optimal conditions for photocatalysis application in RY 125 dye solution degradation. The photocatalyst exhibited a good performance for discoloration at all studied concentrations (25, 50 and 100 mgL -1 ). A good efficiency regarding the aromatic ring-opening process was achieved especially at low concentrations of the dye. However, an effective mineralization did not occur even at low concentrations of dye (25 mgL -1 ). The results of photocatalyst activity under VIS irradiation revealed a practical utility of the silver doped TiO 2 modified zeolite for the RY 125 dye degradation at low concentrations.