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Nowe możliwości zastosowań i testowania elektrod jonoselektywnych dzięki wykorzystaniu elektrochemicznych technik prądowych

Michalska Agata, Maksymiuk Krzysztof

Wiadomości Chemiczne

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2024

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[Z] 78, 7-8

767--789

EN

Ion-selective electrodes are routine analytical tools used in industry, health care, environmental protection, etc. Over the decades, these sensors have been developed and optimized for applications in potentiometry. However, recent years have shown that the application of electrochemical current based techniques can bring significant benefits, both in terms of improving analytical parameters and extending the area of research on the basic properties of this class of sensors. Using the above-mentioned techniques, it is possible, among others, to lower the detection limit, increase sensitivity and signal stability. Moreover, due to controlled modification of the composition of ion-selective membranes by galvanostatic polarization, analytical parameters of sensors working in potentiometric mode can be improved. These methods also offer the possibility to examine charge transport in electrode membranes and at phase boundaries, and to study mechanism of ion sensors work.

2

Analysis of the parameters of supercapacitors containing polypyrrole and its derivatives

Gocki M., Nowak A.J., Karoń K.

Archives of Materials Science and Engineering

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2023

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Vol. 120, nr 1

5--14

EN

Purpose: Investigation of some parameters of energy storage devices (so-called supercapacitors) in which the structures of selected conductive polymers were implemented. Researchers were interested in the relationship between the parameters of the supercapacitor and the molecular structure of the conductive polymer used as the electrode material. Design/methodology/approach: The polypyrrole and its derivatives were produced by an electropolymerization process performed with cyclic voltammetry. During the research, polymer supercapacitors were created containing collectors made of ITO plates. Measurement of device parameters using cyclic voltammetry and chronopotentiometry. In addition, the devices use polymer electrolytes based on poly (methyl methacrylate) (PMMA). Findings: Devices containing polypyrrole have the best electrochemical parameters, while supercapacitors containing poly (phenylpyrrole) have the lowest parameters. This parameter is due to the high hindrance in the poly(phenylpyrrole) molecule in the form of an aromatic ring. Research limitations/implications: The most significant limitation of the devices is their durability due to the low strength of the conductive layer on ITO plates. This layer was easily degraded with too many test cycles. Practical implications: It was confirmed that polypyrrole and its derivatives could be used as electrode materials in energy storage devices. Originality/value: One of the few studies that allow the evaluation of the molecular structure of polypyrrole and its derivatives as electrode material in symmetrical supercapacitors.

3

Electrorefining of Indium Metal From Impure In-Sn Alloy in Fluoride Molten Salt

Lee Hyun-Gyu, Choi Sang-Hoon, Sim Jae-Jin, Lim Jae-Hong, Hyun Soong-Keun, Lee Jong-Hyeon, Park Kyoung-Tae

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 3

899--905

EN

In this study, molten salt electrorefining was used to recover indium metal from In-Sn crude metal sourced from indium tin oxide (ITO) scrap. The electrolyte used was a mixture of eutectic LiF-KF salt and InF3 initiator, melted and operated at 700°C. Voltammetric analysis was performed to optimize InF3 content in the electrolyte, and cyclic voltammetry (CV) was used to de-termine the redox potentials of In metal and the electrolyte. The optimum initiator concentration was 7 wt% of InF3 , at which the diffusion coefficients were saturated. The reduction potential was controlled by applying constant current densities of 5, 10, and 15 mA/cm2 using chronopotentiometry (CP) techniques. In metal from the In-Sn crude melt was deposited on the cathode surface and was collected in an alumina crucible.

4

Chronopotentiometric characterization of electrodialysis module

Koter S., Guler C., Koter I.

Architecture Civil Engineering Environment

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2016

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Vol. 9, no. 3

129--133

EN

Classical and chronopotentiometric characterization of the electrodialysis module at the same concentrations of diluate and concentrate was performed. Limiting current was determined from the Cowan-Brown plot, the current efficiency and the mean transport number of counterions – from the concentration changes on the exit of the ED module. The electric resistance was determined from the chronopotentiometric curve. For electric currents higher than the limiting one, the transition time (inflection point) was observed. Thus, having such curves for different values of electric current, the limiting current can be roughly estimated. To estimate a mean counterion transport number from the transition time, an equation, analogous to the Sand equation, should be developed which include both types of membrane.

PL

Przedstawiono krzywe chronopotencjometryczne elektrodialitycznego modułu membranowego, Stwierdzono, że na ich podstawie można określić, czy zastosowane natężenie prądu nie przekracza prądu granicznego, a tym samym w przybliżeniu określić wartość tego ostatniego. Oszacowana na podstawie kilku krzywych chronopotencjo-metrycznych wartość prądu granicznego jest zgodna z wyznaczoną wartością na podstawie wykresu Cowana-Browna. Obserwowane na krzywych punkty przegięcia można wykorzystać do wyznaczenia średniej liczby przenoszenia przeciwjonów. W tym celu należy wyprowadzić równanie analogiczne do wzoru Sanda, które by brało pod uwagę oba chronopotencjometryczne pozwoliły na proste i szybkie wyznaczenie oporu elektrycznego modułu.

5

A multisensor for electrochemical sequential autonomous automatic measurements

Navratil T., Yosypchuk B., Barek J.

Chemia Analityczna

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2009

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Vol. 54, No. 1

3-17

EN

A newly constructed electrochemical multisensor containing 8 different sensors (5 different solid amalgam electrodes, platinum, gold and glassy carbon electrodes) for analysis of small sample volumes (5-200 μL) was developed. The multisensor was connected to the specially constructed and developed electrochemical multichannel device for sequential autonomous measurements. This device consisted of a computer (PC or notebook), an interface card, and a control box; it was able to control up to 8 sensors (i.e. electrode sets) in a selected sequence, in which each sensor could utilize different detection mode (e.g. DCV, DPV, coulometry, chronopotentiometry, square-wave voltammetry) and operate at different parameters. The analysis of a mixture of ferrocene and nucleic acid bases: adeninę and guanine was used to demonstrate the possibilities of this device.

PL

Opracowano nowy sensor składający się z 8 elektrod, w tym 5 ze stałego amalgamatu i po jednej z platyny, ztota i węgla szklistego. Sensor jest przewidziany do analiz próbek o malej objętości (5-200 μL). Sensor zosta) podłączony do specjalnie skonstruowanego, wielokanałowego urządzenia elektrochemicznego, które umożliwiło sekwencyjne, niezależne pomiary na wszystkich elektrodach. Urządzenie składało się z komputera (PC lub notebook), karty interfejsowej i części kontrolnej. Każdąelektrodę można było użyć w połączeniu z wybraną techniką elektrochemiczną (np. woltamperometria stałoprądowa, woltampe-rometria pulsowa różnicowa, woltamperometria prostokątnej fali, kulometria i chronoam-perometria). W celu zademonstrowania możliwości nowego układu przeprowadzono analizę mieszaniny ferocenu, adenicy i guaniny.

6

Voltammetry of immobilized microparticles : statistical evaluation

Pikna Ľ., Fečková Z., Lux L.

Chemia Analityczna

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2004

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Vol. 49, No. 6

825-832

EN

Dissolution of Fe powder particles immobilized on paraffin impregnated graphite electrode was investigated under galvanostatic conditions. The aim of the experiments was concentrated on quantitative aspects of experimental technique. Reproducibility, repeatability, coverage of the electrode surface were evaluated and calculated according to a simplified model. Influence of the electrode surface area and dissolution current on the above parameters was evaluated and the experimental results were confronted with the suggested model.

PL

Badano rozpuszczanie cząsteczek pudru Fe unieruchomionych na impregnowanym parafiną graficie w warunkach galwanostatycznych. Celem eksperymantów było określenie ilościowych aspektów tej techniki. Obliczono odtwarzalność, powtarzalność i pokrycie powierzchni elektrody używając prostego modelu. Uzyskane wyniki, dotyczące prądów utleniania, porównano z przewidywaniami zaproponowanego modelu.

7

Chronopotentiometry as a method for determining stability constants of metal complexes

Kublanovsky V.S., Litovchenko K.I., Nikitenko V.N.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 12

2556-2563

EN

The complex formation of cadmium(II) with ethylenediaminetetraacetate (H4Edta), iminodiacetate (H2Imda) and glycine (HGl) has been studied by chronopotentiometry. It has been found that cadmium(II) forms with the above ligands complex ions of the compositions: CdHEdta(-), CdHEdta(2-), CdImda, Cd(Imda)(2-/2), CdGl(+) and CdGl2. The stability constants of the above complexes have been determined.