Electrochemical Determination of Oxalate at Pyrolytic Graphite Electrodes

Šljukić, Biljana; Baron, Ronan; Compton, Richard G.

doi:10.1002/elan.200703852

Cited by 37 publications

(21 citation statements)

References 42 publications

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“…However, addition of ammonium oxalate significantly affects the processes of the oxidative half-reaction. The redox potential of ammonium oxalate is +1.15 eV [50]. This means that the oxidative decomposition of ammonium oxalate will be the predominant process rather than the Bi III  Bi V process for which the redox potential is +1.59 eV, and as such the photocatalytic activity of Sr 3 Bi 2 O 6 is diminished.…”

Section: Proposed Photocatalytic Mechanismsmentioning

confidence: 99%

Solid-state synthesis, characterization, UV-induced coloration and photocatalytic activity – The Sr6Bi2O11, Sr3Bi2O6 and Sr2Bi2O5 bismuthates

et al. 2020

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This article reports on two novel visible-light-active strontium bismuthate photocatalysts (Sr 6 Bi 2 O 11 and Sr 3 Bi 2 O 6) prepared by solid-state synthesis for which the number of strontium atoms exceeded the number of bismuth atoms in the cation sublattice; for comparison, the bismuthate Sr 2 Bi 2 O 5 was also reexamined. All three bismuthates were characterized by a variety of spectroscopic techniques (XRD, XPS, EDX, DR, Raman, SEM, and EIS). Both newly as-synthesized bismuthates displayed photocatalytic activity toward the photodegradation of substrates in the gas phase (acetaldehyde) and in aqueous media (phenol), with the Sr 6 Bi 2 O 11 phase exhibiting a significantly greater photoactivity than the Sr 3 Bi 2 O 6 phase; by comparison, the bismuthate Sr 2 Bi 2 O 5 was photocatalytically inactive. Detailed photocatalytic mechanisms have been proposed to explain how composition and structure of the three bismuthates affect their photocatalytic activity. The role of point defects in their crystal lattice is described for processes in which the photocatalytic activity was inhibited. Inferences made were aided by examining the UV-induced coloration of these ternary metal oxides that provided information regarding defect levels within their respective bandgaps; such defects acted as electron traps and thus affected the photocatalytic performance of the bismuthates.

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Section: Proposed Photocatalytic Mechanismsmentioning

confidence: 99%

Solid-state synthesis, characterization, UV-induced coloration and photocatalytic activity – The Sr6Bi2O11, Sr3Bi2O6 and Sr2Bi2O5 bismuthates

et al. 2020

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“…6b The oxalate content is clinically determined in urine using several techniques including high performance liquid chromatography, gas chromatography, ion chromatography and enzyme assays which are quite expensive instruments and often require time-consuming sample preparation. 7 …”

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confidence: 99%

Colourimetric and fluorescent detection of oxalate in water by a new macrocycle-based dinuclear nickel complex: a remarkable red shift of the fluorescence band

et al. 2014

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“…[27][28][29][30] It is important to note that there are no known redox mediators for oxalate oxidase, so all oxalate oxidase biosensors have had to operate via the detection of the hydrogen peroxide enzymatic product. Designs include electrochemical detection of oxalate using edge plane and basal plane pyrolytic graphite electrodes 28 where there was a high overpotential and electrochemical detection of H 2 O 2 using multiwalled carbon nanotube-gold nanoparticle composites, 28 carboxylated multi-walled carbon nanotubes in a polyaniline composite film, 30 and chromium hexacyanoferrate 27 as catalysts. Here, cyclic voltammetry was used to examine the use of TEMPO with oxalate and OxOx in phosphate buffer at pH 5.2 ( Figure 5).…”

Section: Resultsmentioning

confidence: 99%

TEMPO as a Promising Electrocatalyst for the Electrochemical Oxidation of Hydrogen Peroxide in Bioelectronic Applications

Abdellaoui

Knoche

Lim

et al. 2015

J. Electrochem. Soc.

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A number of bioelectronic applications work with oxidase enzymes and many of them can operate with small molecule or polymer redox mediators. However, for some oxidases, there are no known redox mediators able to mediate electron transfer. Therefore, electron transfer must occur through peroxide production and oxidation at the electrode surface. Organic redox catalysts such as oxoammonium cations, are able to oxidize H 2 O 2 to form nitroxyl radicals, which can be electro-oxidized and regenerate the oxoammonium cation form. In this study, we investigate the ability to use TEMPO as a platform for the electrocatalytic oxidation of H 2 O 2 at different pHs. The results have shown that TEMPO can be used to monitor H 2 O 2 in broad pH range (≥4) at 530 mV (vs SCE). Combining TEMPO with cholesterol oxidase, we have shown the possibility to monitor the cholesterol oxidation with a linear range between 20 μM and 2.5 mM with a sensitivity of 54.86 mA cm −2 M −1 . Furthermore, we have studied the electrocatalytic oxidation of oxalate by oxalate oxidase for biofuel cell applications. These combined results demonstrate TEMPO as a promising electrocatalyst applied for the development of electrochemical biosensors or enzymatic biofuel cells. Hydrogen peroxide (H 2 O 2 ) is an enzymatic product of oxygen (O 2 ) reduction, which can be catalyzed by an exhaustive list of oxidase enzymes including glucose oxidase, alcohol oxidase, lactate oxidase, urate oxidase, cholesterol oxidase, D-amino acid oxidase, glutamate oxidase, lysine oxidase, and oxalate oxidase. Hydrogen peroxide is the smallest and simplest peroxide and is of great interest in multiple fields as a disinfectant, as a propellant in the aerospace industry, and as a biomarker for biological decomposition in the food industry.1 It also applied in the defense system of some insects, 2 the immune system, 3 and regulation of cellular processes. 4 Development of enzymatic biosensors presents a significant utility for the detection and quantification of the large number of oxidase substrates for fundamental studies as well as diagnostic and industry applications. Different techniques for the detection of oxidase substrates that have been described in the literature include spectrophotometry, 5 fluorimetry, 6 chemiluminescence, 7 and fluorescence, 8 but most of them are costly and time consuming. Hydrogen peroxide can be oxidized electrochemically, and thus electrochemical techniques have also been used as detection methods. Electrochemistry is commonly described as a simpler, cheaper, faster, and more sensitive detection technique for the development of oxidase substrate biosensors and enzymatic biofuel cells. 9,10The direct electrochemical oxidation and reduction of H 2 O 2 require high overpotentials (>+0.65 V for oxidation and >−1.7 V for reduction versus NHE). These high potentials limit analytical applications involving the oxidation or reduction of H 2 O 2 in complex media, because media electrolysis causes interference and can foul the electrode surface. In order to d...

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Electrochemical Determination of Oxalate at Pyrolytic Graphite Electrodes

Cited by 37 publications

References 42 publications

Solid-state synthesis, characterization, UV-induced coloration and photocatalytic activity – The Sr6Bi2O11, Sr3Bi2O6 and Sr2Bi2O5 bismuthates

Solid-state synthesis, characterization, UV-induced coloration and photocatalytic activity – The Sr6Bi2O11, Sr3Bi2O6 and Sr2Bi2O5 bismuthates

Colourimetric and fluorescent detection of oxalate in water by a new macrocycle-based dinuclear nickel complex: a remarkable red shift of the fluorescence band

TEMPO as a Promising Electrocatalyst for the Electrochemical Oxidation of Hydrogen Peroxide in Bioelectronic Applications

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