Electrochemical Measurements in Flow Systems on Silver Amalgam Tubular Detector Combined with Auxiliary Electrode
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 on request at various institutes of the ASCR
Electrochemical Measurements in Flow Systems on Silver Amalgam Tubular Detector Combined with Auxiliary Electrode
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 ...
Výzkumná zpráva o strukturní, morfologické a chemické analýze vzorků dodaných HE3DA
Zukalová, Markéta
2018 - Czech
Zpráva obsahuje výsledky rentgenostrukturní a morfologické analýzy provedené na sadě dodaných vzorků a jejich elektrochemické testování. The report contains the results of X-ray analysis and adsorption measurements carried out on the provided samples set and their electrochemical testing.
Keywords:
morphology; electrochemistry; X-ray analysis
Available at various institutes of the ASCR
Výzkumná zpráva o strukturní, morfologické a chemické analýze vzorků dodaných HE3DA
Zpráva obsahuje výsledky rentgenostrukturní a morfologické analýzy provedené na sadě dodaných vzorků a jejich elektrochemické testování....
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 on request 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 ...
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 ...
Determination of Roughness Factor and Fractal Dimension of Zirconium in its Native and Surface Modified State using Atomic Force Microscopy. Effect of the Hydrogen Evolution 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 on request 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 Evolution 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 ...
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 on request 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 ...
Redox Properties of Fluorinated Derivativers 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 Derivativers 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 ...
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 ...
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 on request 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 ...
Electrochemical Study of Selected Pyrene Derivatives as Precursors to Organic Semiconductors
Koláčná, Lucie; Tobrman, T.; Ludvík, Jiří
2018 - English
A series of 9 precursors for pyrene based biodegradable organic (semi)conductors having tetrasubstituted double bond as a central organic core and photo- or redox active centers attached at this core were electrochemically investigated in order to determine the influence of individual parts of the molecule on the redox properties, to describe the location of the reduction center and to understand the structure - redox activity relationship of the mentioned compounds.
Keywords:
pyrene; cyclobutene; polarography
Available on request at various institutes of the ASCR
Electrochemical Study of Selected Pyrene Derivatives as Precursors to Organic Semiconductors
A series of 9 precursors for pyrene based biodegradable organic (semi)conductors having tetrasubstituted double bond as a central organic core and photo- or redox active centers attached at this core ...
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