Number of found documents: 3748
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Supported Liquid Membranes for Hollow-Fibre Based Microextraction and Voltammetric Determination of Neuroblastoma Biomarkers
Josypčuk, Bohdan; Barek, J.; Josypčuk, Oksana
2018 - English
A new type of tubular detector (TD+AuxE) was proposed, fabricated, tested and compared\nwith a typical silver amalgam tubular detector developed earlier. Non-stop-flow differential\npulse voltammetric anodic stripping method (AS-DPV) and amperometric method in a\nglucose oxidase biosensor arrangement were tested. Both detectors were applied for AS-DPV\nmeasurements in flow systems for the first time. The proposed combination of tubular\ndetector with auxiliary electrode provides a much greater current response than the classic\narrangement with three individual electrodes. All relevant parameters (potentials of\naccumulation or detection, flow rate, analyte concentrations, shielding sleeve length, etc.)\nwere optimized for the developed TD+AuxE. Keywords: Flow analysis; Amperometry; Voltammetry Available at various institutes of the ASCR
Supported Liquid Membranes for Hollow-Fibre Based Microextraction and Voltammetric Determination of Neuroblastoma Biomarkers

A new type of tubular detector (TD+AuxE) was proposed, fabricated, tested and compared\nwith a typical silver amalgam tubular detector developed earlier. Non-stop-flow differential\npulse voltammetric ...

Josypčuk, Bohdan; Barek, J.; Josypčuk, Oksana
Ústav fyzikální chemie J. Heyrovského, 2018

Determination of Roughness Factor and Fractal Dimension of Zirconium in its Native and Surface Modified State using Atomic Force Microscopy. Effect of the Hydrogen\nEvolution Reaction on the Surface Structure
Novák, M.; Kocábová, Jana; Kolivoška, Viliam; Pospíšil, Lubomír; Macák, J.; Cichoň, Stanislav; Cháb, Vladimír; Hromadová, Magdaléna
2018 - English
Atomic force microscopy (AFM) was used to characterize surface morphology of pristine zirconium, Si modified and FeSi modified zirconium electrodes prior and after hydrogen evolution at potentials negative of the open circuit potential value. Two main characteristic parameters were obtained from the ex situ AFM height images, namely, the roughness factor and fractal dimension of the studied surface. The effect of hydrogen evolution reaction on the electrode surface morphology was discussed. Fractal dimension values were used successfully to explain the non ideality of the interfacial capacitance. Keywords: zirconium electrode; atomic force microscopy; fractal dimension Available at various institutes of the ASCR
Determination of Roughness Factor and Fractal Dimension of Zirconium in its Native and Surface Modified State using Atomic Force Microscopy. Effect of the Hydrogen\nEvolution Reaction on the Surface Structure

Atomic force microscopy (AFM) was used to characterize surface morphology of pristine zirconium, Si modified and FeSi modified zirconium electrodes prior and after hydrogen evolution at potentials ...

Novák, M.; Kocábová, Jana; Kolivoška, Viliam; Pospíšil, Lubomír; Macák, J.; Cichoň, Stanislav; Cháb, Vladimír; Hromadová, Magdaléna
Ústav fyzikální chemie J. Heyrovského, 2018

Differences in Oxidation Mechanism of Selected Bioflavonoids, UV-Vis and IR Spectroelectrochemical Study
Sokolová, Romana; Fiedler, Jan; Ramešová, Šárka; Kocábová, Jana; Degano, I.; Quinto, A.; Křen, Vladimír
2018 - English
The oxidation of selected bioflavonoids (quercetin, rhamnazin, fisetin, rhamnetin, taxifolin, luteolin, silybin and 2,3-dehydrosilybin) was studied by electrochemical and spectroscopic methods. The oxidation mechanism and formation of oxidation products depends on the chemical structure. Only small differences in the chemical structure of compounds with flavone, flavanone and flavonol motif result in extremely variable oxidation pathways and products. Products of oxidation and further decomposition were determined by HPLC-ESIMS/MS and HPLC-DAD. Keywords: oxidation; flavonoids; decomposition Available at various institutes of the ASCR
Differences in Oxidation Mechanism of Selected Bioflavonoids, UV-Vis and IR Spectroelectrochemical Study

The oxidation of selected bioflavonoids (quercetin, rhamnazin, fisetin, rhamnetin, taxifolin, luteolin, silybin and 2,3-dehydrosilybin) was studied by electrochemical and spectroscopic methods. The ...

Sokolová, Romana; Fiedler, Jan; Ramešová, Šárka; Kocábová, Jana; Degano, I.; Quinto, A.; Křen, Vladimír
Ústav fyzikální chemie J. Heyrovského, 2018

Redox Properties of Fluorinated Derivatives of 1,3-Diphenylisobenzofuran Chromophores for Singlet Fission
Šimková, Ludmila; Ludvík, Jiří
2018 - English
Derivatives of 1,3-diphenylisobenzofuran attract interest because they should be efficient as the molecules for singlet fission. The understanding of singlet fission in isolated molecules might be advantageous for use as solar cell sensitizers. This study is focused on fluorinated derivatives of 1,3-diphenylisobenzofuran and the effect of the position of fluorine atoms on their redox properties. For characterization of the redox properties standard electrochemical methods, and in situ UV-vis and EPR spectroscopy techniques were used. Keywords: 1,3-diphenylisobenzofuran; fluorinated derivatives; spectroelectrochemistry Available on request at various institutes of the ASCR
Redox Properties of Fluorinated Derivatives of 1,3-Diphenylisobenzofuran Chromophores for Singlet Fission

Derivatives of 1,3-diphenylisobenzofuran attract interest because they should be efficient as the molecules for singlet fission. The understanding of singlet fission in isolated molecules might be ...

Šimková, Ludmila; Ludvík, Jiří
Ústav fyzikální chemie J. Heyrovského, 2018

Method Development for Speciation Analysis of Volatile Mercury Forms in Ambient Air and flue Gases from Incineration Plants.
Švehla, Jaroslav; Kratzer, J.; Svoboda, M.; Svoboda, Karel; Šyc, Michal; Ružovič, Tomáš
2018 - English
Potential of AAS for on-line speciation analysis of gaseous Hg0 (non-heated atomizer) and HgCl2 (heated atomizer) in flue gases is discussed. Keywords: mercury speciation analysis; flue gas; atomic absorption spectrometry Available in a digital repository NRGL
Method Development for Speciation Analysis of Volatile Mercury Forms in Ambient Air and flue Gases from Incineration Plants.

Potential of AAS for on-line speciation analysis of gaseous Hg0 (non-heated atomizer) and HgCl2 (heated atomizer) in flue gases is discussed.

Švehla, Jaroslav; Kratzer, J.; Svoboda, M.; Svoboda, Karel; Šyc, Michal; Ružovič, Tomáš
Ústav chemických procesů, 2018

Supercritical water in etching and morphing of siliceous surfaces for analytical separations
Karásek, Pavel; Horká, Marie; Planeta, Josef; Roth, Michal
2018 - English
Applications of supercritical water in etching and morphing of siliceous surfaces for analytical separations are briefly reviewed. Keywords: supercritical water; fused silica capillary; electromigration methods Available in digital repository of the ASCR
Supercritical water in etching and morphing of siliceous surfaces for analytical separations

Applications of supercritical water in etching and morphing of siliceous surfaces for analytical separations are briefly reviewed.

Karásek, Pavel; Horká, Marie; Planeta, Josef; Roth, Michal
Ústav analytické chemie, 2018

Capillary electrophoresis in clinical diagnosis and monitoring
Kubáň, Petr
2018 - English
There is a significant potential of CE to provide a useful analytical tool to analyze noninvasive samples of body fluids and stimulate the cooperation between analytical chemists and clinicians in this interdisciplinary field. Keywords: CE; CE-LIF; clinical diagnosis Available in digital repository of the ASCR
Capillary electrophoresis in clinical diagnosis and monitoring

There is a significant potential of CE to provide a useful analytical tool to analyze noninvasive samples of body fluids and stimulate the cooperation between analytical chemists and clinicians in ...

Kubáň, Petr
Ústav analytické chemie, 2018

Effects of urbanization on the landscape of a Modern City in Ghana: A case study of sunyani
Boateng, K. A.; Mensah, Caleb; Agyei, Thomas; Švik, Marian
2018 - English
According to the fifth assessment report of the Intergovernmental Panel on Climate Change, changes in land use through urbanization and agriculture are the key anthropogenic effects of climate change. Thus, the preservation of natural environment of urban areas is essential for conserving water and soil, while still adjusting the microclimatic variables (temperature, precipitation, relative humidity, etc.) and stabilizing the natural ecological system from destruction. It has been observed that most parts of city's green vegetation have been lost due to housing developments and commercial activities. This study was carried out to assess the effect of the change in land use on a modern city like Sunyani, by observing the significant changes in vegetation cover from LANDSAT TM imagery over a 31-year period (1986-2017). From the study, there was significant decline of vegetation cover from 1986 to 1999, and no significant change from 1999 to 2017. There were also significant changes in the built-up areas from 1986 to 1999 and no significant change from 1999 to 2017. Adoption of sustainable and environmentally friendly technologies that maintain open green vegetation is recommended for future city planning. Keywords: Climate change; Green vegetation; landsat; Open green spaces; Urbanization Available at various institutes of the ASCR
Effects of urbanization on the landscape of a Modern City in Ghana: A case study of sunyani

According to the fifth assessment report of the Intergovernmental Panel on Climate Change, changes in land use through urbanization and agriculture are the key anthropogenic effects of climate change. ...

Boateng, K. A.; Mensah, Caleb; Agyei, Thomas; Švik, Marian
Ústav výzkumu globální změny , 2018

Electrochemical Monitoring of the Water Clusters Formation in an Organic Solvent in the Presence of Hydrated Ions
Mareček, Vladimír
2018 - English
An electrochemical method has been developed that makes it possible to monitor the\ndynamics of the co-extraction of water with hydrated chloride ions at the interface between\ntwo immiscible electrolyte solutions (ITIES). The interfacial potential was controlled by the\ndistribution of a common tetralkylammonium (TAA+) ion. Changes in the TAA+\nconcentration at the interface were monitored by measuring the open circuit potential (OCP).\nTransfer of hydrated chloride ions is accompanied by the transfer of TAA+, decreasing its\nconcentration on the aqueous side of the interface. This process involves the co-extraction of\nwater molecules with the hydrated chloride ions and the formation of water clusters in the\norganic solvent phase. The ability to monitor the process from the very beginning of interface\nformation allowed us to obtain important kinetic data. Keywords: Liquid/liquid interface; Water co-extraction dynamics; Emulsification Available on request at various institutes of the ASCR
Electrochemical Monitoring of the Water Clusters Formation in an Organic Solvent in the Presence of Hydrated Ions

An electrochemical method has been developed that makes it possible to monitor the\ndynamics of the co-extraction of water with hydrated chloride ions at the interface between\ntwo immiscible ...

Mareček, Vladimír
Ústav fyzikální chemie J. Heyrovského, 2018

Silver Solid Amalgam Electrodes as Perspective Tools for Sensitive Voltammetric Determinations of Food Azo Dyes Amaranth and Allura Red AC
Tvorynska, S.; Barek, J.; Josypčuk, Bohdan
2018 - English
In this paper, for the first time, the electrochemical behaviours of the food azo dyes Amaranth (E 123) and Allura Red AC (E 129) were investigated on two modifications of silver solid amalgam electrode, namely mercury meniscus modified, polished and compared with hanging mercury drop electrode using differential pulse voltammetry and direct current voltammetry. The effect of adsorption and the reduction mechanism on tested electrodes were described in detail. Measurements with amalgam electrodes showed good reproducibility, stability and high sensitivity. As a result, they were successfully applied for the determination of investigated azo dyes in different commercial drink samples. Keywords: voltammetry; azo dyes; amaranth Available at various institutes of the ASCR
Silver Solid Amalgam Electrodes as Perspective Tools for Sensitive Voltammetric Determinations of Food Azo Dyes Amaranth and Allura Red AC

In this paper, for the first time, the electrochemical behaviours of the food azo dyes Amaranth (E 123) and Allura Red AC (E 129) were investigated on two modifications of silver solid amalgam ...

Tvorynska, S.; Barek, J.; Josypčuk, Bohdan
Ústav fyzikální chemie J. Heyrovského, 2018

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