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Redox Properties of Quasi Dimer of 1,3-diphenylisobenzofuran for Singlet Fission
Šimková, Ludmila; Ludvík, Jiří
2017 - English
Molecules on the base of 1,3-diphenylisobenzofuran attract an interest because of their\npossible efficiency for singlet fission This study is focused on electrochemical behaviour of\nthe „quasi dimer“ of 1,3-diphenylisobenzofuran. For characterization of reduction mechanism\nin situ UV-vis and EPR spectroscopy were used. The monomer 1,3-diphenylisobenzofuran\nand its CH2 dimer were added to this study for comparison. The redox properties of both\ncompared molecules are similar. The location and the nature of the covalent bridging unit in\nCH2dimer have small effect onthe redox potentials. But the pi-conjugation in the molecule of\nquasi dimer causes approximately 0.2 V easier oxidization and reduction.
Keywords:
1,3-diphenylisobenzofuran; dimer; Singlet fission
Available on request at various institutes of the ASCR
Redox Properties of Quasi Dimer of 1,3-diphenylisobenzofuran for Singlet Fission
Molecules on the base of 1,3-diphenylisobenzofuran attract an interest because of their\npossible efficiency for singlet fission This study is focused on electrochemical behaviour of\nthe „quasi ...
Labile Lead Phytochelatin Complexes Could Enhance Transport of Lead Ions across Biological Membrane
Šestáková, Ivana; Navrátil, Tomáš
2017 - English
In connection with studies of hazardous metals transport across model phospholipid\nmembranes, behavior of complexes of lead with phytochelatin PC2 has been examined. Using\nstripping chronopotentiometry with different values of reducing current, the release of free\nlead ions confirms labile behavior. Similar conclusion resulted from voltammetry on silica gel\nmodified carbon paste electrode.
Keywords:
phytochelatin; lead; voltammetry
Available on request at various institutes of the ASCR
Labile Lead Phytochelatin Complexes Could Enhance Transport of Lead Ions across Biological Membrane
In connection with studies of hazardous metals transport across model phospholipid\nmembranes, behavior of complexes of lead with phytochelatin PC2 has been examined. Using\nstripping ...
Charge Transport in Single Molecule Junctions of Spirobifluorene Scaffold
Hromadová, Magdaléna; Kolivoška, Viliam; Sokolová, Romana; Šebera, Jakub; Mészáros, G.; Valášek, M.; Mayor, C.
2016 - English
Single molecule conductance of two spirobifluorene molecules of different length have been studied by scanning tunneling break junction (STM–BJ) methodology. First molecule contains a tripodal spirobifluorene platform, whereas a second one contains the same platform with chemically attached p-phenyleneethynylene molecular wire. The conductance values change only slightly between these two molecules, which demonstrated that such a platform provides both highly conducting pathway and stable anchor for the future molecular electronic devices.
Keywords:
single molecule conductance; spirobifluorene; break junction
Available at various institutes of the ASCR
Charge Transport in Single Molecule Junctions of Spirobifluorene Scaffold
Single molecule conductance of two spirobifluorene molecules of different length have been studied by scanning tunneling break junction (STM–BJ) methodology. First molecule contains a tripodal ...
Phospholipid Modified Glassy Carbon Electrode and its Application for Determination of Pesticides
Švecová, H.; Sokolová, Romana; Součková, J.; Skopalová, J.; Barták, P.
2016 - Czech
In this article we described glassy carbon electrode modified with Asolectin (mixture of phosholipids). Properties of phospholipid layer, such as its thickness or solidity, were investigated using atomic force microscopy (AFM). The modified electrode was applied for square wave voltammetry (SWV) measurements to study interactions of pesticide paraquat with phospholipid layer and to detect paraquat selectively in real samples of river water. Lipidové membrány jsou již mnoho let studovány jako modely biomembrán. Formování lipidových membrán na povrchu pevných elektrod poprvé popsali Tien a Salamon 1. Od té doby byly použity jako substráty pro lipidové vrstvy různé materiály jako např. stříbro 2, zlato 3, rtuť 4 nebo skelný uhlík 5. Lipidový film na povrchu elektrody je schopen akumulovat organické molekuly v závislosti na jejich náboji a na jejich hydrofilním respektive hydrofobním charakteru. Je známé, že mnoho organických látek, jako jsou pesticidy, léčiva a jiné farmakologicky významné látky, interagují s fosfolipidovou vrstvou a mastnými kyselinami v membráně a mohou být silně akumulovány v lipidové tkáni.
Keywords:
paraquat; electrochemistry; phospholipids
Available at various institutes of the ASCR
Phospholipid Modified Glassy Carbon Electrode and its Application for Determination of Pesticides
In this article we described glassy carbon electrode modified with Asolectin (mixture of phosholipids). Properties of phospholipid layer, such as its thickness or solidity, were investigated using ...
Using Voltammetric Method for Monitoring of Antioxidant Content in Biofuels
Tomášková, M.; Chýlková, J.; Navrátil, Tomáš; Šelešovská, R.
2016 - Czech
The simple and fast method for analysis of Propyl gallate (PG) in biofuels was proposed in this paper. Voltammograms of antioxidant under study were recorded using linear sweep voltammetry method at a gold disc electrode in supporting electrolyte containing 0.18 mol L-1 H2SO4 and 10 % ethanol. For purposes to monitor effects on fuel quality caused by oxidative degradation, the proposed method was applied to samples of biodiesel and Ekodiesel® (the blend of biodiesel with fuel diesel). The analysis of PG can be performed without pretreatment of Ekodiesel samples, and after extraction using distilled water in case of biodiesel samples. Z hlediska kvality biopaliv je hlavním problémem jejich oxidační degradace během skladování, která vede ke vzniku produktů, které mohou způsobit ucpání palivových filtrů nebo korozi kovových částí motoru. Kromě toho má oxidační stabilita běžné motorové nafty podstatný vliv na stabilitu směsí s bionaftou. Právě nestabilita bionafty v porovnání s běžně používanou naftou vede k řadě otázek a obav při skladování biopaliv. Pro zpomalení oxidace a zajištění dostatečné stability je nutné nalézt vhodná aditiva a znát jejich přesné množství. Mezi antioxidanty používané pro zvýšení oxidační stability bionafty a jejich směsí s běžnou naftou patří i propyl galát 1-4.
Keywords:
propyl gallate; antioxidant; voltammetry
Available at various institutes of the ASCR
Using Voltammetric Method for Monitoring of Antioxidant Content in Biofuels
The simple and fast method for analysis of Propyl gallate (PG) in biofuels was proposed in this paper. Voltammograms of antioxidant under study were recorded using linear sweep voltammetry method at a ...
Graphene Field-Effect Transistor as a Probe of Doping by Adsorbed Oxygen Molecules
Blechta, Václav; Mergl, Martin; Drogowska, Karolina; Kučera, Lukáš; Valeš, Václav; Červenka, Jiří; Kalbáč, Martin
2016 - English
Graphene has high potential in chemical sensing, thus understanding adsorption and charge transfer between graphene and adsorbed molecules is essential. We show that graphene field-effect transistor exhibits a moderate sensoric response towards oxygen at temperature of 150 °C. Field-effect transistors serve as a tool to probe electronic properties of graphene. We demonstrate that adsorption of oxygen molecules onto graphene leads to an upshift of Dirac point and light changes in mobility of charge carriers.
Keywords:
graphene; sensor; transistor
Available at various institutes of the ASCR
Graphene Field-Effect Transistor as a Probe of Doping by Adsorbed Oxygen Molecules
Graphene has high potential in chemical sensing, thus understanding adsorption and charge transfer between graphene and adsorbed molecules is essential. We show that graphene field-effect transistor ...
Voltammetric determination of homovanillic acid at boron doped diamond electrode for hollow fibre microextraction
Hrdlička, V.; Barek, J.; Navrátil, Tomáš
2016 - English
Presented work deals with hollow-fibre assisted liquid/liquid/liquid microextraction (HF-LPME) and subsequent voltammetric detection of clinical biomarker homovanillic acid (HVA). Three main areas are discussed: hollow fibre assisted extraction of HVA, voltammetric detection of HVA under basic conditions, and sensing in very small volumes. Using HF-PLME, HVA was extracted with 1-octanol as a supported liquid membrane with enrichment factor of 55 after 60 minutes of extraction. A novel method of miniaturized voltammetric determination of HVA using cathodically pretreated boron doped diamond electrode was also developed. Using differential pulse voltammetry, limit of detection, limit of quantificati was 1.9 mu mol dm(-3) on 6.6 mu mol dm(-3).
Keywords:
biomarkers; boron doped diamond electrode; hollow-fibre
Available at various institutes of the ASCR
Voltammetric determination of homovanillic acid at boron doped diamond electrode for hollow fibre microextraction
Presented work deals with hollow-fibre assisted liquid/liquid/liquid microextraction (HF-LPME) and subsequent voltammetric detection of clinical biomarker homovanillic acid (HVA). Three main areas are ...
Edited final report of the project DF11P01OVV012: New materials and technologies for the preservation of historical building materials and preventive care of monuments
Rathouský, Jiří; Slížková, Zuzana; Kotlík, P.
2016 - Czech
This project was focused on development of new materials and technologies for complex solution of problems with preservation of a cultural heritage in the Czech Republic. Main interests were conservation activities as cleaning of historical materials using microemulsions and micellar solutions, consolidation by calcium hydroxide and modified ethylsilicate gels and protection of materials against environment effects and biocorrosion, including protection of the original appearance of the historic materials. Projekt byl zaměřen na vývoj nových materiálů a technologií pro komplexní řešení problematiky uchování hodnot hmotného kulturního dědictví v ČR zejména s ohledem na čištění historických materiálů s využitím mikroemulzí a micelárních roztoků, konsolidaci objektů pomocí nanodisperzí hydroxidu vápenatého a modifikovaných ethylsilikátových gelů a preventivní ochranu materiálů proti působení vnějšího prostředí a biokorozi, včetně zachování jejich původního vzhledu.
Keywords:
consolidation; cleaning of historical materials; protection
Available on request at various institutes of the ASCR
Edited final report of the project DF11P01OVV012: New materials and technologies for the preservation of historical building materials and preventive care of monuments
This project was focused on development of new materials and technologies for complex solution of problems with preservation of a cultural heritage in the Czech Republic. Main interests were ...
Electrochemical determination of 2-nitrofluorene and investigation of its interaction with DNA
Skalová, Štěpánka; Stávková, K.; Barek, J.; Vyskočil, V.
2016 - English
2-Nitrofluorene (2-NF) belongs to the group of nitrated polycyclic aromatic hydrocarbons. These compounds are categorized as environmental pollutants and they can manifest mutagenic and carcinogenic effects. A differential pulse voltammetric method at a glassy carbon electrode (GCE) was developed for sensitive determination of 2-NF. Under the optimum conditions found, a linear calibration dependence was obtained in the concentration range of 2 x 10(-7) - 1 x 10(-5) mol L-1, with the limit of quantification of 2 x 10 mol L-1. The practical applicability of this method was verified on the direct determination of 2-NF in a model sample of sand. Moreover, the mutual interaction between 2-NF and DNA was investigated using an electrochemical DNA biosensor (DNA-modified GCE). Cyclic voltammetry, electrochemical impedance spectroscopy, and square-wave voltammetry were employed in this study, confirming the formation of a 2-NF-DNA complex.\n
Keywords:
DNA biosensors; DNA interaction; glassy carbon electrode
Available at various institutes of the ASCR
Electrochemical determination of 2-nitrofluorene and investigation of its interaction with DNA
2-Nitrofluorene (2-NF) belongs to the group of nitrated polycyclic aromatic hydrocarbons. These compounds are categorized as environmental pollutants and they can manifest mutagenic and carcinogenic ...
THE PHOTOCATALYTIC ABATEMENT OF NOX IMISSIONS USING COMMERCIAL FUNCTIONAL COATING WITH POROUS MORPHOLOGY
Žouželka, Radek
2016 - English
Titanium dioxide is the most important photocatalysts used for purifying applications. It was the purpose of this study to investigate the photocatalytic activity of commercial Protectam FN (R) containing TiO2 nanoparticles towards NO and NO2. Experiments on concrete as a support for photocatalyst were carried out in two types of reactors with laminar and turbulent flow under ´´real world setting´´ conditions of temperature, relative humidity, irradiation and pollutant concentrations. The results showed that photocatalytic process significantly reduced both nitrogen oxides in the air. The decrease in the total concentration of nitrogen oxides on contact with the photocatalytic surface reached 20-50 %, i.e. at a concentration of 100 ppb the decrease in NO and NO2 was 20-50 ppb. The nitrogen oxides were oxidized up to their highest oxidation state, nitric acid ( or nitrates) and undesirable nitrous acid was not formed at all. The experimental study conducted showed that the photocatalytic oxidation on the surface of the photocatalytic Protectam FN (R) coating is an effective method for the removal of nitrogen oxides from contaminated air.
Keywords:
TiO2; NOx; imissions; photocatalysis; air purification
Available at various institutes of the ASCR
THE PHOTOCATALYTIC ABATEMENT OF NOX IMISSIONS USING COMMERCIAL FUNCTIONAL COATING WITH POROUS MORPHOLOGY
Titanium dioxide is the most important photocatalysts used for purifying applications. It was the purpose of this study to investigate the photocatalytic activity of commercial Protectam FN (R) ...
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