Electrochemical characterisation of liquid|liquid microinterface arrays

The incorporation of lipophilic particles into the sensing membrane of ion-selective electrodes (ISEs) can strongly influence the uptake of ions from the sample. The apparent super-Nernstian response of ISEs caused by a strong flux of primary ions from the sample to the inner solution can be suppressed completely. This opens up new possibilities of improving the ruggedness of trace-level measurements.

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“…ca. 100 mm, the approximate thickness of the unstirred aqueous layer) [34]. However, both the images of the membrane (Fig.…”

Section: Resultsmentioning

confidence: 93%

Influence of Incorporated Lipophilic Particles on Ion Fluxes Through Polymeric Ion‐Selective Membranes

2003

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“…In particular, liquid|liquid micro-interfaces offer several advantages in comparison with larger interfaces such as a significant reduction of the ohmic potential drop, a reduction of the capacitive currents, and steady-state responses [5][6][7][8]. Indeed, whether using micro-ITIES supported by a laser-drilled microhole in a thin film [6][7][8][9][10][11][12] or at the tip micropipettes [9,[13][14][15] it has been shown that these micro-interfaces are very useful both for thermodynamic and kinetic measurements [5][6][7][8]11,12,16]. By comparison with microholes, voltammetric studies with micropipettes have to consider asymmetric diffusion fields and account for a relatively high electrical resistance within the pipette [8].…”

Section: Introductionmentioning

confidence: 99%

“…However, it has been shown that Oldham's theory for steady-state voltammetry at hemispherical electrodes [17] can be applied for micro-ITIES systems with low concentration or in absence of supporting electrolyte [5,6,[8][9][10]14,18]. The difference between these two steady-state systems is that in the case of metallic electrodes, the transport of species toward the electrode is given only by diffusion and the charged product is transported from the electrode by diffusion and migration, whilst it is the opposite in the case of micro-ITIES under conditions of diluted supporting electrolyte in the organic phase [6].…”

Section: Introductionmentioning

confidence: 99%

Voltammetric determination of extreme standard Gibbs ion transfer energy

Olaya

Méndez

Cortés‐Salazar

et al. 2010

Journal of Electroanalytical Chemistry

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108

125

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Keywords:Standard Gibbs energy of transfer Standard transfer potential Micro-interface Microhole Hydrophobic ions Hydrophilic ions a b s t r a c t A voltammetric methodology to determine the standard Gibbs energy of transfer of highly hydrophobic and hydrophilic ions has been developed. The electrochemical cell used includes a water|1,2-dichloroethane micro-interface supported on a microhole in a thin polymer film separating an electrolyte-free aqueous phase and an organic phase with an electrolyte at low concentrations. The limiting current and the half-wave potential of these organic ions were determined by fitting the initial part of the ion transfer wave. The methodology was validated using ions with known thermodynamic data, and applied to very hydrophobic and very hydrophilic ions that usually cannot be observed within the potential window.

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“…Besides the standard experimental arrangement for studying the ion transfer at the interface of immiscible electrolyte solutions (ITIES) based on a four electrode configuration [3][4][5][6][7], in recent years a few attempts have been made to utilize a three electrode arrangement to assess both the ion and the electron transfer processes across the L j L interface. Anson and co-workers [8][9][10][11][12][13] used a solid graphite electrode, the surface of which is completely covered with a thin film of an organic liquid containing an electroactive probe and immersed in an aqueous electrolyte (see Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Square-wave thin-film voltammetry: influence of uncompensated resistance and charge transfer kinetics

Mirčeski

Gulaboski

Scholz

2004

Journal of Electroanalytical Chemistry

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An electrode reaction occurring in a thin-film having a low electrical conductivity was considered under conditions of squarewave voltammetry (SWV). The ohmic polarization of the system owing to the low conductivity of the film is represented by the complex resistance parameter defined as, where R X is the resistance of the film, S is the electrode surface area, f is the SW frequency and the other symbols have their usual meanings. The influence of the thickness of the film is given by the thickness parameterwhere L is the thickness of the layer, and D is the diffusion coefficient. For a thin film (K 6 0:949) the dimensionless net-peak current of a reversible electrode reaction depends parabolically on the resistance parameter, exhibiting a well-developed maximum. A detailed study of this phenomenon revealed that it resembles the charge transfer kinetics effect as well as the property known as a ''quasireversible maximum'' that is typical for an adsorption complicated electrode reaction. The theoretically predicted properties of the SW response are illustrated by experiments with iodine, decamethylferrocene, and azobenzene at the three-phase electrode system. This methodology [Electrochem. Commun. 2 (2000) 112] consists of a single droplet of an organic water immiscible solvent containing an electroactive probe that is attached to the surface of a graphite electrode and immersed in an aqueous electrolyte solution. A good agreement between theory and experiment indicates that the SW voltammetric response of the three-phase electrode system exhibits properties of an electrode reaction occurring under limiting diffusion conditions.

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Electrochemical characterisation of liquid|liquid microinterface arrays

Cited by 53 publications

References 19 publications

Influence of Incorporated Lipophilic Particles on Ion Fluxes Through Polymeric Ion‐Selective Membranes

Influence of Incorporated Lipophilic Particles on Ion Fluxes Through Polymeric Ion‐Selective Membranes

Voltammetric determination of extreme standard Gibbs ion transfer energy

Square-wave thin-film voltammetry: influence of uncompensated resistance and charge transfer kinetics

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