6/2011 Sensing in Electroanalysis
https://hdl.handle.net/10195/42514
2024-03-28T13:05:43ZIndirect amperometric detection of non-electroactive species. towards an electrochemical bioasay of mineral weathering?
https://hdl.handle.net/10195/42540
Indirect amperometric detection of non-electroactive species. towards an electrochemical bioasay of mineral weathering?
Walcarius, Alain; Mustin, Christian
Ion exchange polymers doped with a suitable electroactive mediator (i.e., Cu2+ or
Fe(CN)63-) have been used to modify carbon paste electrodes that have been further applied to the indirect amperometric detection of non-redox cations or anions in flow injection analysis. The detection mechanism involves ion exchange between the non-redox ionic analyte and the
electroactive mediator, in the polymer particles located at the electrode surface, followed by the electrochemical transformation of the mediator species leached out of the polymer at the
electrode/solution interface. Operating in the absence of added supporting electrolyte led to peak currents made of a major faradic component that is added to a capacitive contribution due to the conductivity jump occurring upon the analyte passing the electrode surface. The method can be applied to the detection of non-electroactive mineral cations and anions, as well as
poorly-dissociated organic acids, which are usually involved in mineral weathering. After
having characterized and discussed the main parameters affecting the sensitivity of the detection (with respect to analyte charge, size and degree of dissociation), the electrochemical device was evaluated as a possible test to monitor mineral weathering in a simple case (zeolite dissolution
in acidic medium) and in a more sophisticated one (biomediated olivine dissolution by fungi).
2011-01-01T00:00:00ZThe current role of polarography in the light of the coming 90th anniversary of its discovery (a reflection)
https://hdl.handle.net/10195/42539
The current role of polarography in the light of the coming 90th anniversary of its discovery (a reflection)
Vyskočil, Vlastimil; Němcová, Vendula; Hájková, Andrea; Barek, Jiří
Since 1922, when Professor Jaroslav Heyrovský had carried out his pioneering
experiment with a dropping mercury electrode, polarography showed remarkable ability to adjust to ever increasing demands on the sensitivity and selectivity and, up to now, mercury electrodes are among the best sensors for electroanalytical measurements. The aim of this contribution is to remind some facts maybe, not well-known to everyone about the
discovery of polarography, discuss the position of polarography in scientific research today, and outline also some future prospects of this concededly fascinating electrochemical technique.
2011-01-01T00:00:00ZThe optimization procedure for the attachment of saccharomyces cerevisiae on the surface of a carbon paste electrode
https://hdl.handle.net/10195/42538
The optimization procedure for the attachment of saccharomyces cerevisiae on the surface of a carbon paste electrode
Vu, Dai Long; Sýs, Milan; Červenka, Libor
Various kind of organic dyes (Amido black, Phenol red, Rhodamine B, Neutral red,
Eriochrome black T, o-cresol, Crystal blue, and fuchsine) were studied on the purpose of
indirectly evaluating the attachment process of Saccharomyces cerevisiea on the surface of a carbon paste electrode (CPE). Appropriate conditions for adsorption of the individual organic dyes onto the CPE (concentration, accumulation time, stirring speed) have been optimized. Besides, it has been observed that the current derived from the oxidation of Amido black, which
was adsorbed onto the CP-surface after attaching the yeast cells, decreases along with time.
2011-01-01T00:00:00ZAnodic stripping determination of lead and thallium at a bismuth film electrode after extraction of the respective bromide complexes into propylene carbonate
https://hdl.handle.net/10195/42537
Anodic stripping determination of lead and thallium at a bismuth film electrode after extraction of the respective bromide complexes into propylene carbonate
Svobodová, Eva; Švancara, Ivan; Vytřas, Karel; Nagaosa, Yukio
In this contribution, anodic stripping voltammetric determination of lead(II)
and thallium(III) in organic solvent; namely, propylene carbonate, is reported
concerning a bismuth film electrode (BiFE) as the working electrode of choice. The
corresponding measurements were performed directly in organic phase after gas-stirred
liquid-liquid extraction from hydrochloric acid-based solution, confirming the
enhancement in both sensitivity and selectivity of metal determination when employing the methods used some decades ago and combining extraction with polarographic
principles. The metals of interest were determined either separately or simultaneously and for the detection of lead(II), the comparison between in-situ and ex-situ operated BIFEs had also been made and the respective differences discussed.
2011-01-01T00:00:00Z