The electrochemistry of DPPH in three-phase electrode systems for ion transfer and ion association studies

Dharmaraj, Karuppasamy; Nasri, Zahra; Kahlert, Heike; Scholz, Fritz

doi:10.1016/j.jelechem.2018.06.012

Cited by 6 publications

(5 citation statements)

References 26 publications

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“…For example, during the oxidation of DPPH to DPPH + , the positive charge produced is compensated either by the diffusion of a potassium ion from the electrode surface to the bulk solution or the diffusion of equivalent phosphate anion from the bulk solution to the electrode surface. Such types of charge transfers are frequent and well‐documented in electrochemistry experiments performed in organic droplet deposited at conductive electrodes .…”

Section: Resultsmentioning

confidence: 91%

“…When the potential was scanned between 0.00 V and −1.00 V (Figure (A)), an intense and irreversible reduction signal (Ic=−185.2 μA) with a peak potential of −833 mV was obtained. This signal was assigned to the irreversible reduction of the nitro functions of the phenyl group . Indeed, nitroaromatic compounds such as p‐nitrophenol or methylparathion show a reduction peak of the nitro group at similar potentials .…”

Section: Resultsmentioning

confidence: 99%

“…This electrochemical transformation was attributed to the activity of DPPH as a reducing agent. The signal obtained was due to the oxidation of DPPH to yield DPPH + as depicted in Equation 2 .…”

Section: Resultsmentioning

confidence: 99%

“…To overcome this drawback, researchers have recently immobilized DPPH as microparticles on the surface of a working electrode . A three‐phase electrode system was also explored more recently by using a graphite electrode modified by a droplet of nitrobenzene containing solubilized DPPH . However, the handling and preparation of such electrodes are difficult.…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical Study of DPPH Incorporated in Carbon Paste Electrode as Potential Tool for Antioxidant Properties Determination

et al. 2018

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The electrochemical behaviour of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) incorporated in a carbon paste electrode (CPE/DPPH1 %) was studied. Two electrochemical systems assigned to the free‐radical were perfectly defined, including System I where DPPH acts as reducing agent and System II where it acts as an oxidant. Although System II was reversible and remains stable after several consecutive potential scans, System I shows high peak current ratio (Ipa/Ipc=1.4) and a significant decrease in signal intensity when performing consecutive potentials scans. This phenomenon was due to the chemical reaction of the oxidized DPPH and the hydroxide ions present at the vicinity of the electrode surface. This new compound formed was responsible of a new system (System III). Systems II and III were highly pH‐dependent, in agreement with the proton exchange involved in these electrochemical transformations. When experiments were performed in the presence of ascorbic acid (AAH2), only System I was found to be ideal for monitoring the antioxidant activity of AAH2. System I clearly shows a linear dependency between the peak currents of DPPH as a function of AAH2 concentration. This linear response was used to determine the IC50 of ascorbic acid (0.56 μM) in the described experimental condition. This effect was confirmed when controlled amount of tea extracts were used instead of AAH2, confirming the efficiency of CPE/DPPH1 % for the electrochemical evaluation of antioxidant properties.

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Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrochemical Study of DPPH Incorporated in Carbon Paste Electrode as Potential Tool for Antioxidant Properties Determination

et al. 2018

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“…For cation transfer, iodine 9 and iron(III) tetraphenyl porphyrine chloride, 10 some quinones, 11 and fullerene C60 in combination with ionophores 12 have been applied. Lutetium bis(tetra-tert-butylphthalocyaninato) 13 and 2,2-diphenyl-1-picrylhydrazyl 14 have been used for transfer of both cations and anions.…”

Section: Introductionmentioning

confidence: 99%

Three-phase electrochemistry of a highly lipophilic neutral ru-complex having tridentate bis(benzimidazolate)pyridine ligands

Vishwanath

Haga

Watanabe

et al. 2020

Electrochimica Acta

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Here we describe the synthesis and electrochemical testing of a heteroleptic bis(tridentate) ruthenium(II) complex [Ru II (LR)(L)] 0 (LR =2,6-bis(1-(2octyldodecan)benzimidazol-2-yl)pyridine, L = 2,6-bis(benzimidazolate)pyridine). It is a neutral complex which undergoes a quasireversible oxidation and reduction at relatively low potential.The newly synthetized compound was used for studies of ion-transfer at the three-phase junction because of the sensitivity of this method to cation expulsion. The [Ru II (LR)(L)] 0 shows exceptional stability during cycling and is sufficiently lipophilic even after oxidation to persist in the organic phase also using very hydrophilic anions such as Cl − . Given its low redox potential and strong lipophilicity this compound will be of interest as an electron donor in liquid-liquid electrochemistry.

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Three-phase electrodes: simple and efficient tool for analysis of ion transfer processes across liquid-liquid interface—twenty years on

Gulaboski

Mirčeski

Komorsky‐Lovrić³

et al. 2020

J Solid State Electrochem

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The electrochemistry of DPPH in three-phase electrode systems for ion transfer and ion association studies

Cited by 6 publications

References 26 publications

Electrochemical Study of DPPH Incorporated in Carbon Paste Electrode as Potential Tool for Antioxidant Properties Determination

Electrochemical Study of DPPH Incorporated in Carbon Paste Electrode as Potential Tool for Antioxidant Properties Determination

Three-phase electrochemistry of a highly lipophilic neutral ru-complex having tridentate bis(benzimidazolate)pyridine ligands

Three-phase electrodes: simple and efficient tool for analysis of ion transfer processes across liquid-liquid interface—twenty years on

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