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1

Ultrafast potentiostat as compromise between current sensitivity vs. response time

Snizhko Dmytro, Kukoba Anatolii

Przegląd Elektrotechniczny

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2019

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R. 95, nr 8

102--107

EN

Physical and technical problems of a potentiostat scheme are analyzed. Current sensitivity of the traditional potentiostat scheme is considered. The classical scheme of potentiostat was investigated to overcome the bounds of potentiostat perfection. The new scheme of ultrafast potentiostat is proposed, and its development principles are discussed. Improving potentiostat technical parameters such as response time, frequency bandwidth, stability, and potential range are clarified. Schematic simulation results and tests with a real electrochemical composition are shown.

PL

Analizowano techniczne I fizyczne problemy projektowania układu potencjostatu. Zaprojektowano nowy układ szybkiego potencjostatu biorąc pod uwagę czas odpowiedzi, pasmo częstotliwości i stabilność.

2

Korozja w mikroobszarach odlewu na bazie stopu AlCu4Mg1 w roztworze chlorku sodu

Szklarz Z., Krawiec A.

Ochrona przed Korozją

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2012

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nr 3

73-77

PL

W artykule przedstawiono wyniki badań zachowania elektrochemicznego w mikroobszarach stopu AlCu4Mg1. Pomiary dotyczyły wpływu mikrostruktury na odporność korozyjną stopu. Środowiskiem w jakim badano zachowanie korozyjne materiału był 0,1M wodny roztwór chlorku sodu. Zastosowana technika tzw. lokalnego mikroogniwa pozwoliła na zbadanie odporności korozyjnej materiału w mikroobszarach. Mikroobszary zawierające wydzielenia typu P1 (Al2Cu) wykazują katodowy charakter oraz wyższą aktywność elektrochemiczną w porównaniu do mikroobszarów gdzie znajdowały się wydzielenia typu P2 (Al-Si-Mn-Fe-Cu) oraz sama osnowa. Technika lokalnego mikroogniwa pozwoliła także z dużą rozdzielczością określić różnice w zachowaniu samej osnowy, która ma heterogeniczną budowę. Za pomocą mikroelektrod udało się także potwierdzić, że w obszarach anodowych wartość pH jest niższa niż w obszarach katodowych.

EN

The local electrochemical behavior of AlCu4Mg1 aluminium alloys is presented in this paper. The microstructure influence on corrosion behavior was investigated. The electrochemical measurements were performed in 0.1 M chloride water solution. In order to investigate corrosion resistance of the alloy in microregions the Electrochemical Microcell Technique (EMT) was used. The places contains particles P1 (Al2Cu) type exhibit cathodic character and higher electrochemical activity compared do sites where P2 (Al-Si-Mn-Fe-Cu) type particles and pure matrix were present. EMT allows also to determine differences in the matrix corrosion behavior, where heterogeneities in structure were observed. By means of the microelectrodes it was possible to confirm, that in anodic sites pH value is lower than in cathodic sites.

3

Woltamperometryczna identyfikacja i oznaczanie antyutleniaczy w olejach roślinnych w rozpuszczalniku mieszanym kwas octowy - octan etylu

Michałkiewicz S.

Aparatura Badawcza i Dydaktyczna

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2012

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T. 17, nr 3

57-64

PL

Zastosowano woltamperometrię pulsową różnicową (DPV) na mikroelektrodzie do identyfikacji i oznaczania antyutleniaczy: witaminy E (tokoferoli), sezamolu i BHT (2,6-di-te/t-butylohydroksytoluen) w olejach roślinnych. Metoda jest prosta i szybka, a przygotowanie roztworów ogranicza się do rozpuszczenia oleju w rozpuszczalniku mieszanym kwas octowy - octan etylu (3:2, v/v), zawierającym 0,1 M Na-CI04 jako elektrolit podstawowy. Uzyskane wyniki są zgodne z danymi literaturowymi dla sezamolu oraz całkowitej zawartości witaminy E w przeliczeniu na alfa-tokoferol. Ze względu na niewystarczające różnice pomiędzy potencjałami utleniania alfa-, gamma- i delta-tokoferoli, składniki witaminy E nie mogą być analizowane oddzielnie. Zawartość BHT w niektórych olejach przekraczała dopuszczalny poziom 0,01%.

EN

Differential pulse voltammetry (DPV) at a microelectrode has been applied to the identification and quantification of antioxidants: vitamin E (tocopherols), sesamol and BHT (2,6-di-tert-butylhydroksytoluene) in plant oils. The method is simple, fast and the preparation of the solutions is limited just to the dissolution of the oils in a mixed solvent acetic acid - ethyl acetate (3:2, v/v) containing 0.1 M NaCI04 as the supporting electrolyte. The obtained results are in a good accordance with the literature data for sesamol and the total amount of vitamin E expressed as a-tocopherol content. Because of small differences between the oxidation potentials for alpha-, gamma- anddelta6-tocopherol, the components of vitamin E cannot be analyzed separately. The content of BHT in some oils exceeds the permitted level of 0.01%.

4

Epileptic burst measurement using microelectrodes equipped on a cryogenic microprobe for minimally invasive brain surgery of intractable epilepsy treatment

Yamakawa T., Yamakawa T., Ishizuka S., Grigorievich Z. L., Suzuki M., Fujii M.

Journal of Automation Mobile Robotics and Intelligent Systems

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2009

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Vol. 3, No. 4

76-79

EN

A microprobing system, which has the functions of measuring the intracranial EEG(IC-EEG) and freezing brain tissue, is proposed for the minimally invasive brain cryogenic surgery of intractable epilepsy treatment. Two fi76 µm platinum electrodes were equipped on a fi0.8 mm cryogenic probe. Epileptic burst, which was evoked on a brain sample of a rat, was measured by the electrodes. The freezing function was confirmed with the experiments with sliced hippocampus samples of a rat.

5

Recent Developments in Digital Simulation of Electroanalytical Experiments

Bieniasz L., Britz D.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 9

1195-1219

EN

This review covers developments in digital simulations of electroanalytical experiments, since 1996. Over the period of time considered, a number of new techniques has been applied. Among them are: the method of lines approach using the differential algebraic equations formulation, extrapolation and Rosenbrock time integrators, multipoint and high-order compact spatial discretisations, finite-element-like methods, adaptive techniques and sensitivity analysis. More simulation software is now also available.

6

Parallel Electrode Processes in Absence of Supporting Electrolyte. Further Strong Enhancement or Depression of Transport of Ionic Species

Nowicka A., Hyk W., Stojek Z., Ciszkowska M.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 9

1553-1565

EN

Several ferrocene derivatives, including 1,1_-ferrocenedimethanol, ferrocene, sodium ferrocenesulfonate, sodium ferroceneacetate and ferrocenylmethyltrimethylammonium hexafluorophosphate, were used to examine possible situations in voltammetry, if two of them are present together in the cell under the conditions of absence of supporting electrolyte. The pairs of ferrocene derivatives were selected for the examination in such a way that one substrate was ionic and the other one neutral. Also, the diffusion coefficients of the species in the solution were sufficiently similar to avoid the effect of nonadditive voltammetric currents. If the ion formed from the neutral substrate and the second ionic substrate are the key ions in the process of preserving the electroneutrality in the diffusion layer at the electrode surface, a significant enhancement or depression of the transport of the ionic substrate takes place. The corresponding wave heights are either much higher (different signs of the ion charges) or lower (identical signs), compared to a situation, where the ionic substrate is present alone in a solution with no supporting electrolyte. The sequence of voltammetric waves of the two substrates determines, which wave is actually affected. The situations demonstrated in the paper may be useful in analytical strategies, aiming at enhancing or depressing a particular voltammetric signal.