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Współczesne podejścia elektrochemiczne do oznaczania arsenu

Ozimek W., Rutkowska I. A., Cox J. A., Kulesza P. J.

Wiadomości Chemiczne

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2015

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[Z] 69, 9-10

809--822

EN

There has been growing interest in development of new methods for the determination of arsenic due to its high toxity and increasing population in the environment. At present, chromatographic (separation) and spectroscopic (detection) approaches are the most common. Although, they are characterized by high sensitivity and low detection limits, the experimental procedures often require generation of toxic AsH3. Electrochemical methods for the determination of arsenic can be considered as complimentary because they are fairly simple and they are subject to different selectivity criteria. In this respect, various stripping voltammetric procedures are becoming popular. The actual stripping voltammetric measurement consists of two steps in which preconcentration of an analyte at the electrode surface is followed by the so called „stripping” step involving electrode reaction recorded in a form of the voltammetric peak. A representative approach involves reduction of the analyte anions upon application of the sufficiently negative potential to form As(0) on the electrode (e.g. gold) surface; this step is followed by voltammetric oxidation (anodic stripping) of the deposit (to As(III)). In a case of so called cathodic stripping voltammetry, the stationary Hanging Mercury Drop Electrode (HMDE) is often used. During the preconcentration step, an insoluble salt is produced on the electrode surface. To facilitate its formation, copper or selenium species are used as mediators. Under such conditions, insoluble Cu3As2 is generated together with copper amalgam on the surface of HMDE. Because sensitivity and detection limit in electroanalytical determinations strongly depend on the current densities measured, there is a need to search for specific catalytic materials that would induce otherwise highly slow and irreversible redox processes of As(III) (oxidation) and, in particular, As(V) (reduction). Designing effective electrocatalytic materials would be of importance to the development of more sensitive stripping methods and monitoring of arsenic under chromatographic and flow conditions. Representative examples of catalytic systems are provided and discussed here. Some attention is also paid to application of enzymes to sensing of arsenic. Electrochemical determination of arsenic(III) is generally better described in literature. Direct determination of As(V) typically requires its binding into chemical compounds. It is reasonable to expect intense research in future aiming at the developing of new electroanalytical methods for direct selective determination of As(V).

2

Ochrona stali X20Cr13 za pomocą powłoki kompozytowej poli (4,3-ethylenodioksytiofen)/ kwas benzopirolowy/kwas fosforomolibdenowy

Adamczyk L., Królikowski A., Kulesza P. J.

Ochrona przed Korozją

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2011

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nr 7

458-461

PL

W pracy przedstawiono wyniki badań nad otrzymywaniem kompozytowych powłok na bazie polimeru przewodzącego - poli(3,4-etylenodioksytiofenu) (PEDOT), kwasu benzopirolowego(PyBA) i kwasu fosoromolibdenowego (PMo12). Powłoki osadzano elektrochemicznie na powierzchni stali nierdzewnej X20Cr13 przy użyciu metody woltamperometrii cyklicznej z wodnych roztworów micelarnych zawierających eter monolaurynowy glikolu polioksyetylenowego (BRIJ10). Otrzymane powłoki PEDOT/PyBA/PMo12 scharakteryzowano pod względem odporności korozyjnej, morfologii powierzchni oraz adhezji do podłoża stali. Właściwości ochronne powłok oceniano w zakwaszonych (pH = 2) roztworach siarczanowych zawierających dodatek jonów chlorkowych przy użyciu techniki impedancyjnej.

EN

This work presents the results under electrodeposition of composite coatings, consisting of combination of the poly(3,4-ethylenedioxythiophene) (PEDOT) and 4-(pyrrole- 1-yl) benzoic acid (PyBA) and (PMo12). The coatings were electrodeposited on stainless steel by cyclic voltammetry, using a micellar aqueous solution containing a polyoxyethylene lauryl ether. Diagnostic experiments included measurements of protective properties, morphology and adherence of coatings to the steel substrate. The protective properties of the resulting fi lms on stainlees steel were investigated in acidified (pH = 2) sulphate solution in presence of chloride ions, using impedance technique.

3

Aktywacja platynowego katalizatora redukcji tlenu dla potrzeb niskotemperaturowego ogniwa wodorowo-tlenowego

Kolary-Żurowska A., Miecznikowski K., Kulesza P. J.

Przemysł Chemiczny

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2008

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T. 87, nr 1

52-54

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Elektroniczny nos analiza substancji lotnych zawartych w żywności

Caban K., Chojak M., Kulesza P.J.

Przemysł Spożywczy

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2003

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T. 57, nr 3

37-41

PL

Elektroniczne nosy to zespoły czujników gazowych przeznaczone do wykrywania i kontroli zapachów. Zależnie od rodzaju matrycy sensorowej różnią się pomiędzy sobą optymalnymi warunkami funkcjonowania. Pomimo że kalibracja ich jest trudna i tylko niektóre dorównują pod względem czułości nosom ludzkim czy psim, nosy elektroniczne stwarzają możliwość szybkiej i obiektywnej analizy zapachu w przemyśle spożywczym. Współczesne badania naukowe i rozwiązania technologiczne zmierzają w kierunku obniżenia kosztów produkcji, polepszenia powtarzalności pracy i czasu efektywnego działania, jak również miniaturyzacji celem rozpowszechnienia tych urządzeń.

EN

Electronic noses can be viewed as arrays of gas sensors for detection and control of various odors. Optimal condi-tions for their functioning change according to the sensor matrix applied. Electronic noses permit fast and reliable odor analysis in food industry in spite of some limitations related to difficulty in calibration and deficient sensitivity when compared to human and dog noses. In order to widen scope of their practical applications, present scien-tific research and technological development aim at improvement of reproducibility and effective lifetime, miniaturization and reduction of production costs.

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Electrochemical Charging of Indium Hexacyanoferrate Films in DMSO and AcetonitrileWater Mixtures Containing Alkali Metal Cations

Dzieniszewski R., Stroka J., Kulesza P. J., Galus Z.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 11

1753-1765

EN

Indium hexacyanoferrate films were investigated in water-acetonitrile and water- dimethylsulfoxide mixtures containing various alkali metal cations. The films, which were electrodeposited from the supporting electrolytes containing lithium cations, occurred to have fairly open structure permitting the transport of alkali metal cations in the solutions (mixtures) rich in nonaqueous solvents. The slopes of dependencies of formal potentials on the logarithms of concentrations of alkali metal cations were consistent with the predominant involvement of countercations in the redox reactions. But in the cases when the content of nonaqueous solvent was relatively high, the slopes were definitely lower than Nernstian (60mVper cation activity decade), thus implying a more complex mechanism of the reaction.