Prague, Czech Republic
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Extracts of hibiscus leaves were analyzed by depositing on Au or Ag surfaces and subsequent measurement of their surface-enhanced Raman and IR spectra. The spectra reflect different composition of the extracts depending on polarity of the solvents used. The Raman spectra show characteristic bands of plant pigments while the IR spectra correspond to compounds in the cuticular waxy layer. The spectra obtained on Au and Ag surfaces show the bands of the same species while the spectral backgrounds are different. The adsorption/desorption cycles were also studied. The principal component analysis shows that the extracted compounds are mostly bonded by physisorption.


Determination of iron by the title method is complicated by spectral interferences of polyatomic ions, in particular ArO+ and CaO+. This work was focused on the possibility of reducing the interference using a dynamic reaction cell (DRC). The cell was pressurized with He (collision gas) and methane (reaction gas). Settings of DRC were optimized to achieve maximal efficiency of elimination of interferences. The determination of 56Fe and 57Fe was tested and the limit of detection and linearity of calibration curves were determined. The accuracy of the method was verified by analysis of a certified reference material.


Eichler S.,Ustav analyticke chemie | Vosmanska M.,Ustav analyticke chemie | Hofmanova E.,Ustav analyticke chemie | Koplik R.,Ustav analyticke chemie | Mestek O.,Ustav analyticke chemie
Chemicke Listy | Year: 2012

To prevent spreading of radioactive 79Se, a decay product of 238U, engineering barriers with bentonite are used. To predict the behaviour of 79Se, speciation of Se is considered. The inter conversions of non-radioactive Se species were studied in aqueous suspensions of bentonite at various pH using HPLC, ion-pair reversed-phase and anion-exchange chromatographies as well as ICP-MS. Some chromatographic parameters were optimized to improve the separation of the species. The limit of Se detection was determined and the linearity of calibration curves was verified. In alkaline medium, a fair amount of selenite in contact with bentonite was oxidized to selenate with in two weeks. As the retention of selenate in the barrier is lower than that of selenite, Se could easily spread.


Krumal K.,Ustav analyticke chemie | Mikuska P.,Ustav analyticke chemie | Vecera Z.,Ustav analyticke chemie
Chemicke Listy | Year: 2012

Organic markers allow identification of emission sources of atmospheric aerosols. The markers of significant anthropogenic aerosol sources - combustion of biomass including wood and grasses, coal combustion, traffic and cooking - are characterized. The known concentrations of some substances in air such as polycyclic aromatic hydrocarbons enable calculation of diagnostic ratios used as an alternative way of source identification.


Mercury is one of the most dangerous environmental pollutants. Its toxicity depends on the mercury species present. Sample storage, methods of extraction of Hg species and their derivatization for GC are described and discussed.


Tatarkovica M.,Ustav analyticke chemie | Broncovaa G.,Ustav analyticke chemie | Krondakb M.,Ustav jaderneho vyzkumu Rez a.s.
Chemicke Listy | Year: 2012

A brief introduction to the theory of electrochemical impedance spectroscopy (EIS) and its application in chemical analysis using a system of metal electrodes with chemically or electrochemically deposited a sensitive layers. Galvanostatic EIS provides an electrode response to AC perturbation as a function of AC frequency. A constant DC together with superimposed AC is applied to the electrode. The measured quantity is the AC component of the voltage induced by the applied current. A Pt electrode coated with electrochemically generated polythiophene was used for measurement of impedance spectra. Galvanostatic EIS was applied in both quantitative and qualitative chemical analysis of model samples containing inorganic ions. Different methods of impedance spectra analysis were used and compared. In quantitative evaluation of impedance spectra, three methods (local minimum shift, impedance at constant AC frequency and phase shift of local minimum) were tested. The most suitable evaluation method was the first mentioned one. The simultaneous qualitative and quantitative analyses can be monitored using the principal component analysis. The method confirmed the recognition of ions with polythiophene electrode only.


High resolution FT rotational spectroscopy of gases in the decimeter spectral region with a heterodyne detection system, that uses the Fabry-Perot resonator and supersonic jet for the maximal sensitivity and resolving power, is introduced as a unique tool for the conformational analysis of complex molecules. The paper describes technical specifications of the new FTMW spectrometer recently built up at the Institute of Chemical Technology, Prague.


The effect of nonspecific sorption of biomolecules in chromatographic columns and that of variable I contents in high-molecular-weight species on the determination of I species is illustrated by speciation analysis of animal tissues. I species were separated by SEC under the optimized conditions. The recoveries of the separations, limits of detection and limits of quantification were estimated. © 2015, Czech Society of Chemical Engineering. All rights reserved.


Determination of P by inductively-coupled plasma MS is complicated by spectral interference of polyatomic ions. In this work the possibility of P determination in biological samples was tested. P was determined as P+ and PO+ ion. Formation of PO+ ions was supported by the reaction with oxygen in a dynamic reaction cell with optimized parameters. The measurements show smaller interference of P+ than that of PO+. The use of a dynamic reaction cell did not lead to improvement of measured parameters. The limit of detection and linearity of calibration curve were determined for this method. Its accuracy was verified by analysis of certified reference skim milk powder and bean samples.


The extracts of a homeopathic Chamomilla vulgaris preparation and chamomile tea were analyzed by surfaceenhanced Raman scattering and surface-enhanced IR spectroscopies. The aqueous or methanolic extracts were deposited on nanostructured, electrochemically prepared Au surfaces. Only saccharose was identified reliably in homeopathic sample. The presence of other component is evident but they could not be identified.

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