Electrochemistry behavior of endogenous thiols on fluorine doped tin oxide electrodes

Rojas, Luciana; Molero, Leonard; Tapia, Ricardo A.; Rio, Rodrigo Del; Valle, M.; Antilén, Mónica; Armijo, Francisco

doi:10.1016/j.electacta.2011.07.074

Cited by 16 publications

(12 citation statements)

References 58 publications

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“…This may come about because at acid pH these compounds form protonated species that are repelled by the positively charged oxide surface. This has been observed in the electro-oxidation of other thiols as well [24,25]. Fig.…”

Section: Resultsmentioning

confidence: 78%

“…Furthermore, FTO voltammetric studies within a potential range between 0 and 1400 mV at various pH ( Fig. 2 Supplementary data), exhibited only a capacitive response of the electrode [24,25], indicating that under the current working conditions, no oxygen evolution occurred [26,27]. At pH 2, oxygen evolution at FTO takes place at about 1.8 V.…”

Section: Resultsmentioning

confidence: 92%

“…The relationship between I p and scan rate for LA in 0.1 mol L À1 H 2 SO 4 , pH 2, (Fig. 3A Supplementary ), is used to determine E 0 by extrapolating the straight line to m = 0 [24,25,35]. Moreover, the dependence of ln I p on (E p À E 00 ) (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Hence, the potential increase and current decrease as pH goes up, observed for LA electro-oxidation at FTO electrode, can be ascribed to fluoride ions occupying the interstitial space within the FTO. This generates a negative charge that repels negatively charged ionic species, decreasing thus interaction and charge transfer between protonated LA species (LAH + ) and FTO electrode [24,25].…”

Section: Resultsmentioning

confidence: 99%

“…Fluorine doped tin oxide has also been extensively studied as electrode material, precisely because it fulfills almost all the above mentioned requirements. Recently it has been characterized and used in the direct determination of different thiols in aqueous medium [24,25], These compounds exhibit different molecular structures that always bear a free SH group, and, in addition, undergo an adsorption controlled irreversible electrooxidation. Moreover, from the obtained electrochemical parameters it was inferred that each thiol interacts differently upon the FTO electrode.…”

Section: Introductionmentioning

confidence: 99%

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Use of fluorine-doped tin oxide electrodes for lipoic acid determination in dietary supplements

Miranda

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Valle

et al. 2012

Journal of Electroanalytical Chemistry

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Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Use of fluorine-doped tin oxide electrodes for lipoic acid determination in dietary supplements

Miranda

Rio

Valle

et al. 2012

Journal of Electroanalytical Chemistry

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Selective Detection of Cysteine at a Mesoporous Silica Film Electrode Functionalized with Ferrocene in the Presence of Glutathione

et al. 2020

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Unmodified and ferrocene-functionalized mesoporous silica layers exhibiting vertical nanochannels have been grown through electrochemically assisted self-assembly onto indiumtin oxide (ITO), and the resulting film electrodes have been applied for the electrochemical detection of cysteine. When using the unmodified film electrode and ferrocenedimethanol (Fc(MeOH) 2 ) as a mediator in solution, both cysteine and glutathione can be oxidized by the Fc(MeOH) 2 + generated at the electrode surface, but the electron transfer rates were three times faster with cysteine than with glutathione. This can be exploited for the reagent-free selective detection of cysteine over glutathione by using a ferrocene-functionalized mesoporous silica film on an ITO electrode, based on a combination of charge transfer kinetic and mass transport limitations through the oriented nanochannels. This has been demonstrated here by using cyclic voltammetry and amperometry in flow-injection analysis mode. A sensitivity of 1.28 mA M À 1 was measured for the cysteine concentration range of 3-20 μM with a repeatability of the signal between 3 and 12 %. The lowest concentration of cysteine experimentally detected was 3 μM.

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Comparative study of the oxidation behavior of sulfur-containing amino acids and glutathione by electrochemistry-mass spectrometry in the presence and absence of cisplatin

Zabel

Weber

2015

Anal Bioanal Chem

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Small sulfur-containing compounds are involved in several important biochemical processes, including-but not limited to-redox regulation and drug conjugation/detoxification. While methods for stable redox pairs of such compounds (thiols/disulfides) are available, analytical data on more labile and short-lived redox intermediates are scarce, due to highly challenging analytical requirements. In this study, we employ the direct combination of reagentless electrochemical oxidation and mass spectrometric (EC-MS) identification for monitoring oxidation reactions of cysteine, N-acetylcysteine, methionine, and glutathione under simulated physiological conditions (pH 7.4, 37 °C). For the first time, all theoretically expected redox intermediates-with only one exception-are detected simultaneously and in situ, including sulfenic, sulfinic, and sulfonic acids, disulfides, thiosulfinates, thiosulfonates, and sulfoxides. By monitoring the time/potential-dependent interconversion of sulfur species, mechanistic oxidation routes are confirmed and new reactions detected, e.g., sulfenamide formation due to reaction with ammonia from the buffer. Furthermore, our results demonstrate a highly significant impact of cisplatin on the redox reactivity of sulfur species. Namely, the amount of thiol oxidation to sulfonic acid via sulfenic and sulfinic acid intermediates is diminished for glutathione in the presence of cisplatin in favor of the disulfide formation, while for N-acetylcysteine the contrary applies. N-acetylcysteine is the only ligand which displays enhanced oxidation currents upon cisplatin addition, accompanied by increased levels of thiosulfinate and thiosulfonate species. This is traced back to thiol reactivity and highlights the important role of sulfenic acid intermediates, which may function as a switch between different oxidation routes.

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Electrochemistry behavior of endogenous thiols on fluorine doped tin oxide electrodes

Cited by 16 publications

References 58 publications

Use of fluorine-doped tin oxide electrodes for lipoic acid determination in dietary supplements

Use of fluorine-doped tin oxide electrodes for lipoic acid determination in dietary supplements

Selective Detection of Cysteine at a Mesoporous Silica Film Electrode Functionalized with Ferrocene in the Presence of Glutathione

Comparative study of the oxidation behavior of sulfur-containing amino acids and glutathione by electrochemistry-mass spectrometry in the presence and absence of cisplatin

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