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Single Molecule Conductance and Junction Formation in Solution. Solvent Effect
Lachmanová, Štěpánka; Šebera, Jakub; Gasior, Jindřich; Dupeyre, G.; Lainé, P. P.; Mészáros, G.; Hromadová, Magdaléna
2017 - English
The single molecule conductance of expanded pyridinium derivative terminated by pyridyl\nnitrogen as an anchoring group at both ends of the molecule in two different environments\nwas measured by scanning tunneling microscopy break junction technique (STM-BJ). The\nvalues obtained in commonly used 1,3,5-trimethylbenzene (TMB) significantly differ from\nthe values acquired in a mixture of TMB and ethanol. Markedly lower junction length and\nhigher conductance indicate strong influence of adsorption of the molecule to the substrate\nsurface in pure TMB compared to the TMB and ethanol mixture.
Keywords:
Single molecule conductance; Expanded pyridinium derivatives; Solvent effect
Available at various institutes of the ASCR
Single Molecule Conductance and Junction Formation in Solution. Solvent Effect
The single molecule conductance of expanded pyridinium derivative terminated by pyridyl\nnitrogen as an anchoring group at both ends of the molecule in two different environments\nwas measured by ...
Electrochemical biosensors with flow-through enzymatic reactors
Josypčuk, Oksana; Josypčuk, Bohdan
2017 - English
Twelve enzymatic biosensors with various silica powder reactors were fabricated and tested.\nExperiments with six silica materials showed that mesoporous silica SBA-15 was the best one\nin terms of covering by enzymes, sensitivity and lifetime of biosensors. The current response\nof the SBA15-glucose oxidase (GOx) sensor started to decrease only after 200-day testing.\nThe used amalgam tubular detector in a flow system allowed working at highly negative\npotentials. Statistical results of parallel measurements of model solutions with the fabricated\nbiosensors show their high accuracy and sensitivity. The proposed SBA15-GOx biosensor\nwas used for determination of glucose in commercial honey.
Keywords:
Biosensor; Amperometry; Enzymatic reactor
Available on request at various institutes of the ASCR
Electrochemical biosensors with flow-through enzymatic reactors
Twelve enzymatic biosensors with various silica powder reactors were fabricated and tested.\nExperiments with six silica materials showed that mesoporous silica SBA-15 was the best one\nin terms of ...
Voltammetric Determination of Tumor Biomarkers using Flow Injection Analysis with Amperometric Detection
Makrlíková, Anna; Matysik, F.-M.; Barek, J.; Vyskočil, V.
2017 - English
Three tumor biomarkers (homovanillic acid, vanillylmandelic acid,\nand 5-hydroxyindole-3-acetic acid) have been determined by flow\ninjection analysis with amperometric detection at screen-printed\ncarbon electrodes in optimum medium of Britton-Robinson buffer\n(0.04 mol l-1, pH = 2.0). Dependences of the peaks current on the\nconcentration of biomarkers were linear in the tested concentration\nregion from 0.05 to 100 mu mol l-1, with the limits of detection of\n0.065 mu mol l-1 for homovanillic acid, 0.053 mu mol l-1 for vanillylmandelic\nacid, and 0.033 mu mol l-1 for 5-hydroxyindole-3-acetic acid (calculated\nfrom heights), and 0.024 mu mol 1-1 for homovanillic acid,\n0.020 mu mol l-1 forvanillylmandelic acid, and 0.012 mu mol l-1 for 5-hydroxyindole-3-acetic acid (calculated from areas), respectively.
Keywords:
flow injection analysis; 5-hydroxyindole-3-acetic acid; homovanillic acid
Available on request at various institutes of the ASCR
Voltammetric Determination of Tumor Biomarkers using Flow Injection Analysis with Amperometric Detection
Three tumor biomarkers (homovanillic acid, vanillylmandelic acid,\nand 5-hydroxyindole-3-acetic acid) have been determined by flow\ninjection analysis with amperometric detection at ...
Hollow-fibre Based Microextraction and Voltammetric Determination of Vanillylmandelic Acid
Hrdlička, Vojtěch; Barek, J.; Navrátil, Tomáš
2017 - English
New method of liquid/liquid/liquid hollow fibre based microextraction of vanillylmandelic acid coupled with voltammetric determination is being developed. Selected liquid membranes based on alcohols, aliphatic hydrocarbons and esters were tested. Highest enrichment factor of 2.52 after 30 minutes of extraction was obtained using propyl benzoate, RSD = 18.2 % (n=5). Mechanically and cathodically pretreated (-1000 mV vs. Ag/AgCl/3M KCl, 15 s) boron doped diamond electrode in a miniaturized arrangement was used for DPV determination. LOD = 1.2 micromol/l, RSD = 5.9% (n=10) for a 10 microl extract.
Keywords:
Hollow-fibres; Liquid phase microextraction; Voltammetry
Available at various institutes of the ASCR
Hollow-fibre Based Microextraction and Voltammetric Determination of Vanillylmandelic Acid
New method of liquid/liquid/liquid hollow fibre based microextraction of vanillylmandelic acid coupled with voltammetric determination is being developed. Selected liquid membranes based on alcohols, ...
Voltammetric Determination of Tumor Biomarkers using Flow Injection Analysis with Amperometric Detection
Němečková-Makrlíková, Anna; Matysik, F.-M.; Navrátil, Tomáš; Barek, J.; Vyskočil, V.
2017 - English
Three tumor biomarkers (homovanillic acid, vanillylmandelic acid, and 5-hydroxyindole-3-acetic acid) have been determined by flow injection analysis with amperometric detection at screen-printed carbon electrodes in optimum medium of Britton-Robinson buffer (0.04 mol l(-1), pH = 2.0). Dependences of the peaks current on the concentration of biomarkers were linear in the tested concentration region from 0.05 to 100 mu mol l(-1), with the limits of detection of 0.065 mu mol l(-1) for homovanillic acid, 0.053 mu mol l(-1) for vanillylmandelic acid, and 0.033 mu mol l(-1) for 5-hydroxyindole-3-acetic acid (calculated from heights), and 0.024 mu mol l(-1) for homovanillic acid, 0.020 mu mol l(-1) for vanillylmandelic acid, and 0.012 mu mol l(-1) for 5-hydroxyindole-3-acetic acid (calculated fromareas), respectively.
Keywords:
vanillylmandelic acid; homovanillic-acid; urine; flow injection analysis; 5-hydroxyindole-3-acetic acid; homovanillic acid; vanillylmandelic acid; tumor biomarkers
Available at various institutes of the ASCR
Voltammetric Determination of Tumor Biomarkers using Flow Injection Analysis with Amperometric Detection
Three tumor biomarkers (homovanillic acid, vanillylmandelic acid, and 5-hydroxyindole-3-acetic acid) have been determined by flow injection analysis with amperometric detection at screen-printed ...
Determination of 5-hydroxyindole-3-acetic acid using Flow Injection Analysis with Electrochemical Detection
Makrlíková, Anna; Matysik, F.-M.; Navrátil, Tomáš; Barek, J.; Vyskočil, V.
2017 - English
Tumour biomarker, 5-hydroxyindole-3-acetic acid, has been determined at screen-printed carbon electrodes using flow injection analysis with amperometric detection. Britton-Robinson buffer (0.04 mol-l-1 , pH 2.0) was used as an optimum carrier solution.\nDependence of the peak current on the analyte concentration was linear in the whole tested\nconcentration range (from 0.5 to 100 mikromol-l-1) with limits of detection 0.033 mikromol-l-1 \n(calculated from peak heighst) and 0.012 mikromol-l-1 (calculated from peak areas).
Keywords:
Amperometric detection; Flow injection analysis; 5-Hydroxyindole-3-acetic acid
Available on request at various institutes of the ASCR
Determination of 5-hydroxyindole-3-acetic acid using Flow Injection Analysis with Electrochemical Detection
Tumour biomarker, 5-hydroxyindole-3-acetic acid, has been determined at screen-printed carbon electrodes using flow injection analysis with amperometric detection. Britton-Robinson buffer (0.04 ...
Effect of pH on the Oxide Film Formation on a Pristine Zr Electrode
Hromadová, Magdaléna; Kocábová, Jana; Kolivoška, Viliam; Pospíšil, Lubomír
2017 - English
Effect of pH on the oxidation of zirconium metal was studied by cyclic voltammetry in\naqueous borate buffer solutions as a function of the potential scan rate and pH from 4.80 to\n9.17. The results show that the oxide growth kinetics depends on pH of the electrolyte\nsolution and the total amount of irreversibly formed oxide under the potentiodynamic\nconditions decreases with decreasing buffer pH in accord with thermodynamic considerations.\nCathodic current corresponding to hydrogen evolution reaction diminishes in the presence of\nanodically modified electrode compared to bare zirconium.
Keywords:
zirconium; oxide film; hydrogen evolution
Available on request at various institutes of the ASCR
Effect of pH on the Oxide Film Formation on a Pristine Zr Electrode
Effect of pH on the oxidation of zirconium metal was studied by cyclic voltammetry in\naqueous borate buffer solutions as a function of the potential scan rate and pH from 4.80 to\n9.17. The results ...
High resolution infrared spectroscopy as diagnostic tool for combustion and plasma chemistry
Zelinger, Zdeněk; Nevrlý, Václav; Grigorová, Eva; Bitala, P.; Dostál, Michal; Suchánek, Jan; Kubát, Pavel; Engst, Pavel; Ferus, Martin; Kubelík, Petr; Civiš, Svatopluk
2017 - English
Monitoring of transient species within combustion experiments (laminar flames, shock-tubes, flow reactors, etc.) is still relatively challenging task especially if application of non-invasive, i.e. optical detection methods is required. High resolution infrared spectroscopy is based on observation of the fine rotation structure that accompanies vibration transitions and thus provides direct information essential to characterization of both molecular structure and reaction dynamics. Thanks to its outstanding advantage enabling unambiguous assignment of specific molecular system according to its spectral feature, it can serve as a helpful tool for exploring complex reaction mechanisms as well as chemical reactivity of individual species present in laboratory flames or plasmas.\nPrevious studies gaining new insights into combustion and plasma chemistry as well as our recent advances targeted towards application of high resolution infrared spectroscopy for species concentration measurement in laminar flames are summarized here below.
Keywords:
spectroscopy; plasma chemistry; infrared spectra
Available in digital repository of the ASCR
High resolution infrared spectroscopy as diagnostic tool for combustion and plasma chemistry
Monitoring of transient species within combustion experiments (laminar flames, shock-tubes, flow reactors, etc.) is still relatively challenging task especially if application of non-invasive, i.e. ...
Photocatalytic active coatings-environmental way to improve quality and durability of buildings
Sázavská, T.; Jakubičková, M.; Jirkovský, Jaromír; Šubrt, Jan; Peterka, F.
2017 - English
Transparent coatings of TiO2-SiO2 nanocomposite were developed to be applied on building facades in order to prevent growth of microorganisms and thus to improve urban building sustainability. Structure and texture characteristics of the prepared nanocomposites were determined by electron microscopy (SEM, TEM + EDS), their photocatalytic activity was quantified by testing self-cleaning ability and antimicrobial activity. The self-cleaning properties were evaluated according to the standard ISO method based on photocatalytic degradation of methylene blue. The TiO2-SiO2 nanocomposite coatings were applied on various types of substrates commonly used in building industry. The antimicrobial activity was mainly investigated for algae because these microorganisms are often responsible for facades ageing. According to the laboratory tests the prepared TiO2-SiO2 nanocomposites are highly efficient. This fact was already proved by first applications in real conditions. The transparent SiO2-TiO2 nanocomposites represent an ecological and noninvasive way how to keep nice appearance of buildings for a long time. It is due to their permanent photocatalytic activity causing self-cleaning and algicidal effects. Such coatings may significantly reduce ageing processes on facades of buildings that are caused by microbiological pollution and smog exhalations.
Keywords:
Photocatalysis; Photocatalytic algae degradation; Photocatalytic paint
Available at various institutes of the ASCR
Photocatalytic active coatings-environmental way to improve quality and durability of buildings
Transparent coatings of TiO2-SiO2 nanocomposite were developed to be applied on building facades in order to prevent growth of microorganisms and thus to improve urban building sustainability. ...
Wavelength modulation spectroscopy for multicomponent ana-lytics of biomass burning tracers
Dostál, Michal; Válek, V.; Suchánek, Jan; Kristlová, E.; Roupcová, P.; Zelinger, Zdeněk; Nevrlý, Václav; Bitala, P.; Vašinek, M.; Kubát, Pavel; Ferus, Martin; Civiš, Svatopluk
2017 - English
The potential of Tunable Diode Laser Absorption Spectroscopy (TDLAS) for monitoring of several species produced by biomass burning is in focus of this work. The infrared spectra of selected molecules (HCOOH, C2H2, CH3CN, N2O, CH3OH, CH3COCH3) are measured in laboratory conditions and the selectivity and of this method is demonstrated.
Keywords:
spectroscopy; biomass burning tracers; TDLAS system
Available in digital repository of the ASCR
Wavelength modulation spectroscopy for multicomponent ana-lytics of biomass burning tracers
The potential of Tunable Diode Laser Absorption Spectroscopy (TDLAS) for monitoring of several species produced by biomass burning is in focus of this work. The infrared spectra of selected molecules ...
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