Electrochemical Pseudo‐Titration of Water‐Soluble Antioxidants

Tacchini, Philippe; Lesch, Andreas; Neequaye, Alice; Lagger, Grégoire; Liu, Jifeng; Cortés‐Salazar, Fernando

doi:10.1002/elan.201200590

Cited by 21 publications

(30 citation statements)

References 40 publications

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“…Moreover, the presented inkjet printing batch fabrication process affords for disposable or single use CNT sensors. Recently, a pseudo-titration method was introduced to separate the most relevant AOs, which react quickly at low oxidation potentials, from less reactive species in solution [24]. A mathematical treatment of the LSVs is performed by multiplying the measured currents with a Fermi-Dirac function f(E) in order to measure a modulated current I mod :…”

Section: Antioxidant Measurementsmentioning

confidence: 99%

“…Two adjustable parameters, namely k and E threshold , are used as a factor modulating the shape of the LSV and as a potential offset to shift the curve towards smaller or higher potentials, respectively (SI-4) [24]. An antioxidant power (AOP) can be calculated by integrating I mod and is presented in nW (Eq.…”

Section: Antioxidant Measurementsmentioning

confidence: 99%

“…More recently, other assays such as the reducing antioxidant capacity evaluated by electrolysis (RACE) [21], the rapid electrochemical screening of antioxidant capacity (RESAC) [22] or microfluidic devices [23] were proposed. In addition, a new pseudo-titration voltammetry (PTV) concept where AOs that are rapidly oxidized at low oxidation potentials are mathematically separated from slow reacting and less relevant compounds has also been described [24].…”

Section: Introductionmentioning

confidence: 99%

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Large scale inkjet-printing of carbon nanotubes electrodes for antioxidant assays in blood bags

Lesch

Cortés‐Salazar

Prudent

et al. 2014

Journal of Electroanalytical Chemistry

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a b s t r a c tHerein, we present the large scale fabrication of carbon nanotubes (CNT) electrodes supported on flexible polymeric sheets by subsequent multilayer inkjet printing of a silver layer for electrical connection, CNT layers as active electrode material and an insulation layer to define a stand-alone CNT active electrode area with high accuracy. Optical and electrochemical characterization using several redox mediators demonstrates the reproducibility of the electrode surfaces and their functionality even with a single inkjet printed CNT layer. These electrodes are targeted to the clinical sector for the determination of the antioxidant power (AOP) of biologically relevant fluids by pseudo-titration voltammetry. As a proof-ofconcept, the AOP of ascorbic acid solutions and biological samples such as erythrocyte concentrates (ECs) from different blood donors were determined demonstrating the potential use of the presented CNT sensors on ECs for blood transfusion purposes and the clinical sector.

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Section: Antioxidant Measurementsmentioning

confidence: 99%

Section: Antioxidant Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Large scale inkjet-printing of carbon nanotubes electrodes for antioxidant assays in blood bags

Lesch

Cortés‐Salazar

Prudent

et al. 2014

Journal of Electroanalytical Chemistry

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“…Therefore, it is possible to distinguish the relevant AO signals from the signals not related to AOs using a mathematical treatment of the recorded curves which suppresses the measured signals at higher potentials. This procedure was introduced as electrochemical pseudo‐titration voltammetry (vide infra) .…”

Section: Introductionmentioning

confidence: 99%

The antioxidant capacity of erythrocyte concentrates is increased during the first week of storage and correlated with the uric acid level

et al. 2017

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Background and Objectives Red blood cells (RBCs) suffer from lesions during cold storage, depending in part on their ability to counterbalance oxidative stress by activating their antioxidant defence. The aim of this study was to monitor the antioxidant power (AOP) in erythrocyte concentrates (ECs) during cold storage. Materials and MethodsSix ECs were prepared in saline-adenine-glucose-mannitol (SAGM) additive solution and followed during 43 days. The AOP was quantified electrochemically using disposable electrode strips and compared with results obtained from a colorimetric assay. Haematological data, data on haemolysis and the extracellular concentration of uric acid were also recorded. Additionally, a kinetic model was developed to extract quantitative kinetic data on the AOP behaviour.Results The AOP of total ECs and their extracellular samples attained a maximum after 1 week of storage prior to decaying and reaching a plateau, as shown by the electrochemical measurements. The observed trend was confirmed with a colorimetric assay. Uric acid had a major contribution to the extracellular AOP. Interestingly, the AOP and uric acid levels were linked to the sex of the donors. ConclusionThe marked increase in AOP during the first week of storage suggests that RBCs are impacted early by the modification of their environment. The AOP behaviour reflects the changes in metabolism activity following the adjustment of the extracellular uric acid level. Knowing the origin, interdonor variability and the effects of the AOP on the RBCs could be beneficial for the storage quality, which will have to be further studied.

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“…However, these approaches can only be applied to optically active compounds. Alternatively, AOs can be detected at amperometric electrodes where the AOs get electrochemically oxidized or reduced depending on the applied electrode potential [26]. The recorded current is proportional to the concentration of AOs in the sample and common optical limitations (e.g.…”

Section: Introductionmentioning

confidence: 99%

Mapping the antioxidant activity of apple peels with soft probe scanning electrochemical microscopy

Lin

Lesch

et al. 2017

Journal of Electroanalytical Chemistry

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We present a non-invasive electrochemical strategy for mapping the antioxidant (AO) activity of apple peels, which counterbalances oxidative stress caused by various external effectors. Soft carbon microelectrodes were used for soft probe scanning electrochemical microscopy (SECM) enabling the gentle and scratch-free contact mode scanning of rough and delicate apple peels in an electrolyte solution. The SECM feedback mode was applied using ferrocene methanol (FcMeOH) as redox mediator that gets electrochemically oxidized at the soft probe and diffuses towards the apple peel where it gets regenerated by certain AOs leading to a redox mediator recycling and increased current signal. The global AO activity in the apple peel including lenticels and regions with artificially degraded AOs were mapped using the soft microelectrodes. Finally, in an apple cross-section the higher and homogeneous AO concentration in the peel with a heterogeneously decaying AO gradient towards the apple inward was visualized, demonstrating the adequate micrometer resolution of the SECM probe and the possibility to get information of the interior AO activity of the apple.

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Electrochemical Pseudo‐Titration of Water‐Soluble Antioxidants

Cited by 21 publications

References 40 publications

Large scale inkjet-printing of carbon nanotubes electrodes for antioxidant assays in blood bags

Large scale inkjet-printing of carbon nanotubes electrodes for antioxidant assays in blood bags

The antioxidant capacity of erythrocyte concentrates is increased during the first week of storage and correlated with the uric acid level

Mapping the antioxidant activity of apple peels with soft probe scanning electrochemical microscopy

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