Ascorbic Acid

Dryhurst, Glenn

doi:10.1016/b978-0-12-222401-0.50008-1

Cited by 19 publications

(15 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6) for RGO-1.25V modified SPE, even if in this case the two electrochemical responses are almost completely overlapped. Although the mechanism of AA oxidation is still a debated issue, it has been ascertained to involve adsorptions steps [41,42], which could be the major cause of the results obtained here.…”

Section: Go Rgomentioning

confidence: 80%

Systematic study of the correlation between surface chemistry, conductivity and electrocatalytic properties of graphene oxide nanosheets

Maccaferri

Zanardi

Xia

et al. 2017

Carbon

View full text Add to dashboard Cite

A main advantage of graphene oxide (GO) over other materials is the high tunability of its surface functional groups and of its electric conductivity. However, the complex chemical composition of GO renders difficult to unravel the correlation between structural and electric properties. Here, we use a combination of electron spectroscopy and electrochemistry to correlate the surface chemistry of GO to its electrical conductivity and electrocatalytic properties with respect to two molecules of high biological interest: β-nicotinamide adenine dinucleotide (NADH) and vitamin C. We demonstrate that the electrocatalytic properties of the material are due to hydroxyl, carbonyl and carboxyl groups residues that, even if already present on pristine GO, become electroactive only upon GO reduction. The results of this study demonstrate the advantages in the use of GO in amperometric biosensing and in enzymatic biofuel cells: it allows the oxidation of the target molecules at low potential values, with a sensitivity >15 times higher with respect to standard, carbon-based electrode materials. Finally, we demonstrate that the right amount of chemical groups to achieve such high performance can be obtained also by direct electrochemical exfoliation of bulk graphite, without passing through GO production, thus rendering this approach suitable for cheap, large-scale applications.

show abstract

Section: Go Rgomentioning

confidence: 80%

Systematic study of the correlation between surface chemistry, conductivity and electrocatalytic properties of graphene oxide nanosheets

Maccaferri

Zanardi

Xia

et al. 2017

Carbon

View full text Add to dashboard Cite

show abstract

“…The electrochemical oxidation of L-ascorbic acid has been reviewed by Dryhurst et al [45] and studied extensively at platinum [33,46], gold [47] and glassy carbon [48] electrodes. While the glassy carbon electrodes yield low levels of surface passivation the kinetics of electron transfer are slow unless the surface is chemically modified [48].…”

Section: 'Silent' Voltammetry Of Ascorbic Acidmentioning

confidence: 99%

Electroanalysis of Ascorbic Acid: A Comparative Study of Laser Ablation Voltammetry and Sonovoltammetry

Akkermans

Bain

et al. 1998

Electroanalysis

View full text Add to dashboard Cite

The electroanalytical detection of L-ascorbic acid via its two electron oxidation in aqueous solution is the subject of a comparison of two voltammetric methodologies both of which rely in part on electrode abrasion. First in sonovoltammetry cavitational collapse at the electrodesolution interface can lead to electrode erosion and activation. Second in laser ablation voltammetry (LAV) a 10 Hz pulsed laser (532 nm, 0.7 mJ per pulse) is used to abrade the electrode. In both cases the concomitant agitation of the solution leads to regular refreshment of the diffusion layer so that at sufficiently extreme potentials sustained currents (transport limited currents) are observed which scale with the concentration of ascorbic acid present and permit quantitative electroanalysis.Comparison of the methods as applied to ascorbic acid shows that for LAV the laser light intensity can be adjusted for maximum ablation of surface adsorbed blocking species but with minimum damage to the platinum surface itself. In contrast the sonovoltammetry technique does not facilitate selective erosion of surface adsorbed species. Instead the mass transport, amount of cavitation and damage to the electrode are all interlinked with the intensity of ultrasound employed. Thus while the amount of cavitation at the electrode surface can be controlled the relative adsorbate/electrode abrasion cannot. The limiting currents under insonation were found to be substantially (ca. 15 times) larger than for LAV suggesting that the major benefit of sonovoltammetry is in terms of enhanced mass transport whereas LAV shows more selective cleaning activation. The development of a novel sono-LAV is therefore reported which retains the merits of both the separate experiments in isolation. Thus the cleaning potential of LAV is coupled with the mass transport enhancement of ultrasound. Application to the quantitative electroanalysis of ascorbic acid is reported.

show abstract

“…Most importantly it also makes the design of a portable device possible. In addition we note that solid metal electrodes used to analyze directly for ascorbic acid are quickly subject to signi®cant fouling by the oxidized form of ascorbic acid [2,3]. In recent years there has been much work on the intercalation of a wide range of organic molecules into layered inorganic compounds [4].…”

Section: Introductionmentioning

confidence: 99%

Photoelectrochemical Determination of Ascorbic Acid Using Methylene Blue Immobilized in α-Zirconium Phosphate

et al. 1999

View full text Add to dashboard Cite

Photoelectrochemical analysis of ascorbic acid is reported in aqueous solution at a platinum channel electrode using the dissolved phenothiazine dyes methylene blue and methylene green. This is achieved by measuring the current produced by immediate electrooxidation of the reduced form of the dyes produced during the 1:1 photoreaction between the dyes and ascorbic acid induced by visible light. This behavior is similar to that reported previously for toluidine blue, and rate constants for the photochemical reaction of 360 AE 20 mol À1 dm 3 s À1 for methylene blue and 150 AE 20 mol À1 dm 3 s À1 for methylene green are determined using simulation of the observed photocurrent as a function of¯ow rate. The light used for this determination was at 620±625 nm and came from a monochromated 1000 W xenon arc lamp. The technique is extended to the immobilization of methylene blue in a zirconium phosphate lattice, which has a layer structure. Methylene blue was chosen since it intercalates to the greatest extent as evidenced by the size of new peaks apparent in its powder X-ray pattern. The dyeaphosphate compound is mixed with graphite and mineral oil such that there is a 10:1 ratio of dyeaphosphate to graphite to produce a viable photo-electrode. It is found that the photoreaction proceeds as in solution and that a light pen (laser pointer) producing 4 mW of light of wavelength 620±670 nm is suf®cient to produce signi®cant photocurrents with ascorbic acid which permit the quantitative determination of the latter at concentrations up to 1.0 mM. Finally a prototype sensor design is described, incorporating an allin-one unit comprising the photo-electrode and light pen together. This is used to measure the amount of ascorbic acid in the commercial headache remedy Resolve. A value of 31.0 AE 1.0 mg per sachet is found, compared with 30 mgasachet determined independently.

show abstract

Ascorbic Acid

Cited by 19 publications

References 46 publications

Systematic study of the correlation between surface chemistry, conductivity and electrocatalytic properties of graphene oxide nanosheets

Systematic study of the correlation between surface chemistry, conductivity and electrocatalytic properties of graphene oxide nanosheets

Electroanalysis of Ascorbic Acid: A Comparative Study of Laser Ablation Voltammetry and Sonovoltammetry

Photoelectrochemical Determination of Ascorbic Acid Using Methylene Blue Immobilized in α-Zirconium Phosphate

Contact Info

Product

Resources

About