Factors Affecting the Electrochemical Responses of Metal Complexes at Pyrolytic Graphite Electrodes Coated with Films of Poly(4‐Vinylpyridine)

Oyama, Noboru; Anson, Fred C.

doi:10.1149/1.2129725

Cited by 205 publications

(90 citation statements)

References 16 publications

(38 reference statements)

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“…No appreciable variation of the peak potential and a good linear dependence of I p,a with y was observed for 1 mV s (1 5/y 5/500 mV s (1 (R 0/0.999), corresponding to no diffusional limitations [28]. This is shown in the plot of oxidation peak current, I p,a , for different values of y (Fig.…”

Section: Characterisation Of the Electrode Process Of Adsorbed Adriammentioning

confidence: 64%

Anodic voltammetry and AFM imaging of picomoles of adriamycin adsorbed onto carbon surfaces

Oliveira-Brett

Piedade

Chiorcea

2002

Journal of Electroanalytical Chemistry

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Adriamycin adsorbs strongly and irreversibly onto surfaces and this enabled electrochemical detection of in situ adriamycin oxidative damage to DNA. The adsorption of adriamycin onto glassy carbon and highly oriented pyrolytic graphite (HOPG) electrodes was studied by voltammetry and mode atomic force microscopy (MAC). At a glassy carbon electrode (GCE), the adsorbate has similar voltammetric behaviour to adriamycin in solution, which enabled the cyclic, differential pulse and square wave voltammetric study of the electron transfer reaction. The total surface concentration of adriamycin adsorbed onto GCE, from a 50 nM adriamycin solution during 3 min, was calculated to be 2.57)/10 (12 mol cm (2 . The oxidation of adsorbed adriamycin is pHdependent and corresponds to a two electron/two proton mechanism, and the detection limit for adriamycin adsorbed onto the GCE was 3.33)/10 (10 M. In situ AFM images show quick and spontaneous adsorption of the adriamycin onto a HOPG surface. Adriamycin forms a stable monolayer when adsorbed from different concentrations of adriamycin solutions and for short adsorption times. The strong and irreversible chemisorption of adriamycin onto carbon electrodes enables detection limits of the order of picomolar, which is much lower than the detection limits attainable by voltammetric methods for most organic compounds. #

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Section: Characterisation Of the Electrode Process Of Adsorbed Adriammentioning

confidence: 64%

Anodic voltammetry and AFM imaging of picomoles of adriamycin adsorbed onto carbon surfaces

Oliveira-Brett

Piedade

Chiorcea

2002

Journal of Electroanalytical Chemistry

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“…Oyama and Anson first used the strategy to modify poly(4-vinyl pyridine) (PVP) on the carbon surface for ion exchange of Fe(CN) 6 4À in acidic conditions [72,73]. Other polymers such as partially quaternized PVP (QPVP) and Nafion were then extensively utilized for sensor applications [3,11].…”

Section: Homogeneous Multilayer (Uniform) Cmesmentioning

confidence: 99%

Recent Updates of Chemically Modified Electrodes in Analytical Chemistry

2003

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This review article updates recent developments in chemically modified electrodes (CMEs) towards analytical applications for the year of 2000 ± 2002 with 179 references. The broad topics are subdivided into four main categories: i) physisorption/chemisorption, ii) covalently linked, iii) homogenous (uniform) multilayer and iv) heterogeneous (non-uniform) multilayer CMEs. The criteria for the preparation of CMEs in elecrocatalytic systems are clearly described in Section 1. Some of the encouraging results related to Au-nanoparticles for DNA detection and new ceramic carbon, carbon nanotubes, copper-plated screen-printed and Nafion/lead ruthenate pyrochlore CMEs for catalytic application were especially discussed in this review.

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“…The peak currents were proportional to scan rate, as expected under these conditions (11), and the formal potential was taken as the simple average of the peak potentials, which were typically separated by 10 to 30 mV by residual ohmic potentials present in the cell and coating. At bare electrodes, the peak potentials were usually separated by 60-70 mV, as expected (12).…”

Section: March 1984mentioning

confidence: 99%

Shifts in Redox Formal Potentials Accompanying the Incorporation of Cationic Complexes in Perfluoro Polycarboxylate and Polysulfonate Coatings on Graphite Electrodes

Tsou

Anson

1984

J. Electrochem. Soc.

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The formal potentials of several redox couples incorporated in coatings of a perfluoropolycarboxylate on graphite electrodes were measured and compared with the formal potentials of the same couples in homogeneous solution. The differences observed agreed with those calculated from the Nernst equation with the independently measured incorporation coefficients for both halves of the redox couples. The dependences of the shifts in formal potentials on the nature of the incorporating complex ion, the ionic strength, and the temperature were determined and indicated that the incorporation equilibrium is governed by electrostatic and hydrophobic interactions that act in opposite directions. The incorporation of most cation s examined was driven by large increases in entropy which overcame the usually unfavorable enthalpy changes.Redox reactants incorporated in polyelectrolyte coatings on electrode surfaces will exhibit formal potentials that are shifted from their values in solution whenever the two oxidation states of the reactant have different equilibrium constants for incorporation by the polyelectrolyte. This situation has been recognized in earlier reports (1, 2) .and in a recent study this aspect of the electrochemistry of redox polymer coatings was examined in detail (3). In continuing studies of the electrochemical responses obtained from redox reactants at electrodes coated with Nation, I, and the re- coatings. Both the magnitude of the shift in formal potential and its sign were influenced strongly by the nature of the ligands coordinated to the metal center of the redox couples. It was the purpose of the experiments described here to document the behavioral differences observed with several redox couples in both polyelectrolytes and to attempt to understand their origins. The results indicate that both electrostatic and hydrophobic interactions of incorporated electroactive ions with the polyelectrolyte combine to determine the direction of shifts in formal potentials. The temperature dependences of the shifts in formal potential were also measured. They pointed to large entropic contributions to the differences in the equilibrium incorporation of the oxidized and reduced halves of the redox couples. ExperimentalMaterials.--Nafion I coatings were prepared as previously described (4) by evaporation of aliquots of a solution of the polymer supplied by E. I. du Pont de Nemours and Company several years ago. Polymer II was supplied in the form of a fine suspension of the methyl ester by Asahi Glass Company, Tokyo. To prepare coatings, aliquots of the suspension were evaporated on freshly cleaved electrodes. The resulting deposit was exposed to 1M NaOH for 5 min to convert the ester to the carboxylate, and the electrode was then washed thoroughly with water. The extent and uniformity of the de-esterification were not examined in detail, but it was established that increasing the time that the coatings were exposed to the 1M NaOH produced no changes in their behavior. Electrodes were prepared from pyrol...

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Factors Affecting the Electrochemical Responses of Metal Complexes at Pyrolytic Graphite Electrodes Coated with Films of Poly(4‐Vinylpyridine)

Cited by 205 publications

References 16 publications

Anodic voltammetry and AFM imaging of picomoles of adriamycin adsorbed onto carbon surfaces

Anodic voltammetry and AFM imaging of picomoles of adriamycin adsorbed onto carbon surfaces

Recent Updates of Chemically Modified Electrodes in Analytical Chemistry

Shifts in Redox Formal Potentials Accompanying the Incorporation of Cationic Complexes in Perfluoro Polycarboxylate and Polysulfonate Coatings on Graphite Electrodes

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