Number of found documents: 7378
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Aplikace mikro-objemové voltametrické cely pro stanovení doxorubicinu hydrochloridu
Skalová, Štěpánka; Navrátil, Tomáš; Barek, J.; Vyskočil, V.
2018 - Czech
Byla úspěšně otestována aplikace mikro-objemové voltametrické cely na příkladu stanovení protinádorového léčiva doxorubicinu hydrochloridu. Objem analyzovaného vzorku činil 50 mikroL s LOD 0,39 micromol L-1 a LDR 0,4-10 mikromol L-1. Tato mikro-objemová cela byla také úspěšně použita k analýze tohoto analytu v modelových vzorcích pitné vody a lidské moči. Doxorubicin is an anticancer drug, which is used for treatment of various cancer types. It contains a quinone structure, similarly as some other drugs belonging to the same category (e.g., daunorubicin and epirubicin). Its monitoring can lead to optimization of individual patient dosages and increase chances for recovery of patients. A micro-volume voltammetric cell and differential pulse cathodic stripping voltammetry have been used for determination of doxorubicin hydrochloride. A volume of used sample was 50 microL. Limit of detection was 0.39 micromol L-1. An applicability of this method was verified on samples of drinking water and of human urine. Keywords: Doxorubicine hydrochloride; Voltametry; Micro-volume Available at various institutes of the ASCR
Aplikace mikro-objemové voltametrické cely pro stanovení doxorubicinu hydrochloridu

Byla úspěšně otestována aplikace mikro-objemové voltametrické cely na příkladu stanovení protinádorového léčiva doxorubicinu hydrochloridu. Objem analyzovaného vzorku činil 50 mikroL s LOD 0,39 ...

Skalová, Štěpánka; Navrátil, Tomáš; Barek, J.; Vyskočil, V.
Ústav fyzikální chemie J. Heyrovského, 2018

Chování metalothieneinů a fytochelatinů na rtuťových a amalgámových elektrodách
Šestáková, Ivana; Navrátil, Tomáš; Josypčuk, Bohdan
2018 - Czech
Při použití elektrod AgSAE či CuSAE pro elektrochemická měření s metalothioneiny či fytochelatiny vznikají příslušné Ag-MT, Cu-MT, Ag-PC či Cu-PC komplexy. V čistých elektrolytech a pro nízké koncentrace analytů jsou odezvy lineárně závislé na jejich koncentraci, odezvu je možné zvýšit akumulací při vhodném potenciálu. Pro reálné vzorky je podstatný negativní vliv matrice, který může vést až k nutnosti přípravy nového povrchu a jeho aktivace pro každý jednotlivý záznam. The presence of cysteine residues in molecules of metallothioneins or phytochelatins is crucial for their electrochemical behavior. At mercury electrodes, the reduction of\ntetracoordinated Cd and Zn in molecule of mamamalian MT is observed in solution of pH 8- 8.5, whereas with lowering pH or at presence of excessive ions, signals of differently coordinated or free metal ions appear. Such changes were confirmed on model complexes with phytochelatin PC2 .Using amalgam electrodes CuSAE or AgSAE for voltammetry of metallothioneins or phytochelatins, their Cu or Ag complexes are formed on the electrode surface, which could be with limitations - employed for the analytical purposes. Keywords: metallothioneins; amalgam electrode; voltammetry Available on request at various institutes of the ASCR
Chování metalothieneinů a fytochelatinů na rtuťových a amalgámových elektrodách

Při použití elektrod AgSAE či CuSAE pro elektrochemická měření s metalothioneiny či fytochelatiny vznikají příslušné Ag-MT, Cu-MT, Ag-PC či Cu-PC komplexy. V čistých elektrolytech a pro nízké ...

Šestáková, Ivana; Navrátil, Tomáš; Josypčuk, Bohdan
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

Determination of stability constants of antamanide complexes with sodium and potassium ions by affinity capillary electrophoresis
Pangavhane, Sachin; Böhm, S.; Makrlík, E.; Ruzza, P.; Kašička, Václav
2018 - English
Affinity capillary electrophoresis (ACE) was applied for quantitative investigation of the interactions between important biomolecule, cyclic decapeptide antamanide (AA), cycl[-Val(1)-Pro(2)-Pro(3)-Ala(4)-Phe(5)-Phe(6)-Pro(7)-Pro(8)-Phe(9)-Phe(10)-], and sodium and potassium cations in methanol. Apparent stability constants of AA complexes with these alkali metal ions were determined from the dependence of effective mobility of AA on the concentration of these ions in the background electrolyte by the non-linear regression analysis. The AA complexes with Na+ and K+ ions were found to be relatively weak, with the apparent stability constants 343 L/mol and 35 L/mol, respectively. Keywords: affinity capillary electrophoresis; antamanide; binding constant Available at various institutes of the ASCR
Determination of stability constants of antamanide complexes with sodium and potassium ions by affinity capillary electrophoresis

Affinity capillary electrophoresis (ACE) was applied for quantitative investigation of the interactions between important biomolecule, cyclic decapeptide antamanide (AA), ...

Pangavhane, Sachin; Böhm, S.; Makrlík, E.; Ruzza, P.; Kašička, Václav
Ústav organické chemie a biochemie, 2018

Separation of rotamers of 5-nitrosopyrimidines by capillary electrophoresis
Štěpánová, Sille; Procházková, Eliška; Čechová, Lucie; Žurek, Jiří; Janeba, Zlatko; Dračínský, Martin; Kašička, Václav
2018 - English
A new capillary electrophoresis (CE) method was developed for the separation of a new type of stereoisomers - rotamers of polysubstituted 5-nitrosopyrimidine derivatives. Partial separation of some rotamers was obtained in sodium borate, pH 9.3, or in Tris-phosphate, pH 2.2, background electrolytes (BGEs) free of cyclodextrins (CDs). However, the best, baseline separations of the rotamers of 5-nitrosopyrimidines were achieved in sodium borate BGE, pH 9.3, containing 20 mg/mL beta-CD as stereoselector, or in Tris-phosphate BGE, pH 2.2, with carboxymethyl-beta-CD as stereoselector. Keywords: rotamers; 5-nitrosopyrimidines; capillary electrophoresis Available at various institutes of the ASCR
Separation of rotamers of 5-nitrosopyrimidines by capillary electrophoresis

A new capillary electrophoresis (CE) method was developed for the separation of a new type of stereoisomers - rotamers of polysubstituted 5-nitrosopyrimidine derivatives. Partial separation of some ...

Štěpánová, Sille; Procházková, Eliška; Čechová, Lucie; Žurek, Jiří; Janeba, Zlatko; Dračínský, Martin; Kašička, Václav
Ústav organické chemie a biochemie, 2018

Proton Detection of Carbon-Carbon Couplings between Chemically Equivalent Nuclei.
Blechta, Vratislav; Sýkora, Jan
2018 - English
Keywords: carbon-carbon couplings; chemical equivalent nuclei Available in a digital repository NRGL
Proton Detection of Carbon-Carbon Couplings between Chemically Equivalent Nuclei.

Blechta, Vratislav; Sýkora, Jan
Ústav chemických procesů, 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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