Electrocatalysis of NADH oxidation with electropolymerized films of azure I

“…11 Phenothiazine derivatives, such as azure (AZU) dyes, were usually utilized in this respect, because they are chemically reactive and display negative formal potentials (vs. SCE) at neutral pH. NADH detectors were developed based on AZU dyes that have been either adsorbed, 12 electropolymerized 13,14 or covalently attached 15 to the electrode surface. However, such modified surfaces displayed a rather limited stable ability and redox mediation capacity.…”

Section: Introductionmentioning

confidence: 99%

Low-Potential Nicotinamide Adenine Dinucleotide Detection at a Glassy Carbon Electrode Modified with Toluidine Blue O Functionalized Multiwall Carbon Nanotubes

et al. 2006

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The determination of β-nicotinamide adenine dinucleotide (NADH) is very important, because the NAD + /NADH couple is a cofactor system for a large number of dehydrogenase enzymes (>300) and a component of biomarker systems.1 However, the direct oxidation of NADH at a bare electrode surface is highly irreversible, and needs a considerable overpotential (>1 V), 2,3 which is increased further by the presence of an enzyme. One of the most serious problems resulting from a high overpotential detection is fouling of the electrode surface associated with the accumulation of reaction products. 4 Much effort was devoted to pursuing new electrode materials and methods to decrease the detection potential and to avoid electrode surface fouling. One of the recently emerged and efficient ways to circumvent a high overpotential for the oxidation of NADH was to use carbon nanotubes (CNTs), since CNTs could significantly reduce the NADH overpotential, 5-10 although the decrease was not adequate.Another conventional approach to lower the oxidation potential of NADH is to apply redox mediators with low formal potentials. 11 Phenothiazine derivatives, such as azure (AZU) dyes, were usually utilized in this respect, because they are chemically reactive and display negative formal potentials (vs. SCE) at neutral pH. NADH detectors were developed based on AZU dyes that have been either adsorbed, 12 electropolymerized 13,14 or covalently attached 15 to the electrode surface. However, such modified surfaces displayed a rather limited stable ability and redox mediation capacity. The integration of phenothiazine derivatives and MWNTs in a polymeric matrix 16,17 for the determination of NADH with enhanced electrocatalytic characteristics was also reported, but the reported method was somewhat complicated. Hence, pursuing a simpler approach and new electrode materials to further decrease the overpotential for NADH oxidation and to minimize surface passivation effects to improve the detection sensitivity and redox mediation capacity is still an obvious challenge.In recent years, increasing interests have been focused on the rational functionalization of CNTs to fabricate functional nanostructures with novel properties. Some creative methods were used for the functionalization of CNTs with polymers, 18,19 biomolecules, 20,21 metal nanoparticles 22,23 and polynuclear aromatic compounds 24,25 through a covalent or noncovalent interaction. These functionalization strategies have generated many new materials with excellent functions, which are very attractive for practical applications. 26,27We describe here a simple method for constructing a new electrochemical functional nanostructure of TBO-MWNTs, which is based on a redox mediator, TBO assembled onto the surface of a MWNTs modified glassy carbon electrode. In this case the MWNTs act as a support of the redox mediator as well as a catalyst. The experimental results showed that the TBOMWNTs modified GC electrodes exhibited excellent electrocatalytic activity toward the oxidation of NADH. To the...

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“…. During the first anodic scan, an irreversible oxidation wave was observed at þ 1.0 V (Pa1) which can be assigned to the oxidation of tertiary amino group of PyB monomers [10,51]. In the first cathodic scan a cathodic peak at À 0.2 V (Pc1) was observed.…”

Section: Modification Of Electrode Surfacementioning

confidence: 99%

“…The structure of poly(PyB) film might similar to the hypothetical structure proposed for poly(methylene blue). Like other polyazines [10,11,18,51,53], the electrocatalytic reactions of PyB with NADH might follow the formation of the substrate-catalyst complex. The oxidation peak of current of NADH on poly(PyB) modified electrode was directly proportional to the square root of scan rate from 10 to 100 mV/s which is confirmed that NADH diffuses from its solution to polymer film where it reduces the oxidized poly(PyB) film to form NAD þ and reduced form of poly(PyB).…”

Section: Electrocatalysis Of Nadhmentioning

confidence: 99%

Amperometric Sensor for Detection of the Reduced Form of Nicotinamide Adenine Dinucleotide Using a Poly(pyronin B) Film Modified Electrode

Kumar

Chen

2009

Electroanalysis

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An electrochemical method for the preparation of poly(pyronin B) film was proposed in this paper. A poly(pyronin B) (poly(PyB)) film modified glassy carbon electrode (GCE) has been fabricated via an electrochemical oxidation procedure and applied to the electrocatalytic oxidation of reduced form of nicotinamide adenine dinucleotide (NADH). The poly(PyB) film modified electrode surface has been characterized by atomic force microscope (AFM), scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS), UV-visible absorption spectrophotometry (UV-vis) and cyclic voltammetry (CV). These studies have been used to investigate the poly(PyB) film, which demonstrates the formation of the polymer film and the excellent electroactivity of poly(PyB) in neutral and even in alkaline media. Due to its potent catalytic effects towards the electrooxidation of NADH at lower potential (0.0 V), poly(PyB) film modified electrode can be used for the selective determination of NADH in real samples because of dopamine, ascorbic acid and uric acid oxidation can be avoided at this potential. The catalytic peak currents are linearly dependent on the concentrations of NADH in the range of 1.0 Â 10 À6 to 5.0 Â 10 À4 mol/L with correlation coefficients of 0.999. The detection limits for NADH is 0.5 Â 10 À6 mol/L. Poly(PyB) modified electrode also shows good stability and reproducibility due to the irreversible attachment of polymer film at GCE surface.

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Electrocatalysis of NADH oxidation with electropolymerized films of azure I

Cited by 69 publications

References 41 publications

Electrocatalytic Reduction of Dioxygen on a Glassy Carbon Electrode Modified with Adsorbed Cobaloxime Complex

Electrocatalytic Reduction of Dioxygen on a Glassy Carbon Electrode Modified with Adsorbed Cobaloxime Complex

Low-Potential Nicotinamide Adenine Dinucleotide Detection at a Glassy Carbon Electrode Modified with Toluidine Blue O Functionalized Multiwall Carbon Nanotubes

Amperometric Sensor for Detection of the Reduced Form of Nicotinamide Adenine Dinucleotide Using a Poly(pyronin B) Film Modified Electrode

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