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Determination of arsenic species in seafood reference materials by ICP-MS with hydride generation and cryotrapping
Pokorná, Nikola ; Matoušek, Tomáš (advisor) ; Červený, Václav (referee)
The aim of this work was to determine chemical species of arsenic in sea originating certified reference materials. Measurements were done using method of hydride generation. Hydrides were preconcentrated in liquid nitrogen cooled tube and detected using inductively coupled plasma mass spectrometry. During the testing of the method, mutual conversion of arsenic species was observed for inorganic arsenic, monomethyl arsenic and dimethylarsenic. Further study revealed that with presence of matrix and hydrogen peroxide, demethylation occured only in hydride generation phase, not during extraction. Dissociation of hydrogen peroxide in extracts was verified using catalase. End of the demethylation process was proved using measurement with addition of arsenic species standards. The newly invented procedure was used to determine arsenic species in reference materials with sufficient accuracy. Final results are compatible with results from different method, and already published results as well. Key words: speciation analysis, arsenic, hydride generation, seafood, inductively coupled plasma mass spectrometry
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Fate of smelter dusts in temperate and semi-arid soils
Ettler, V. ; Jarošíková, A. ; Mihaljevič, M. ; Kříbek, B. ; Veselovský, F. ; Penížek, V. ; Vaněk, A. ; Šráček, O. ; Matoušek, Tomáš ; Mapani, B. ; Kamona, F. ; Nyambe, I.
Our results indicate that, compared to semi-arid areas (where inorganic contaminants are rather immobile in soils despite their high concentrations), a higher potential risk exists in smelter-affected humid areas, where metal(loid) contaminants can be easily released by extensive weathering of particulates in the soil systems.
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Determination of Inorganic Arsenic in Samples of Marine Origin
Marschner, Karel ; Matoušek, Tomáš ; Dědina, Jiří ; Musil, Stanislav
A fast screening method for determination of inorganic arsenic in marine samples was developed. This method is based on selective\nhydride generationanddetectionby inductively coupled plasmamass spectrometry. Using a high concentration of hydrochloric acid\ntogether with hydrogen peroxide for hydride generation leads to selective conversion of inorganic arsenic species into arsane. The\naccuracy of this method was verified by comparative analyse by high performance liquid chromatography coupled with hydride generationandatomic\nfluorescence detection.
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Speciation analysis of inorganic arsenic in seafood material
Pokorná, Nikola ; Matoušek, Tomáš (advisor) ; Musil, Stanislav (referee)
This thesis was focused on extraction of individual arsenic species from reference materials of fish protein DORM-3 and DORM-4. Extracts were then analyzed by a hydride generation method with detection by inductively coupled plasma mass spectrometry. Materials were extracted in two ways - in a microwave device and in a heating block. It was found that extraction with 2% nitric acid is not efficient. Extraction performed in 2% nitric acid with addition of hydrogen peroxide at various concentrations increased the extraction yield, but it caused conversion of arsenic species. This conversion would mean the overestimation of inorganic arsenic content.
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Generation of volatile species of palladium for atomic absorption spectrometry
Vyhnanovský, Jaromír ; Musil, Stanislav (advisor) ; Matoušek, Tomáš (referee)
This thesis deals with optimization of the conditions for chemical generation of volatile species of palladium in combination with atomic absorption spectrometry. The volatile species of palladium were generated in a flow injection system by the reaction of an acidified sample with the solution of sodium borohydride in the presence of reaction modifiers. A diffusion flame atomizer was used due to its high robustness. In the first part of this thesis the optimization of parameters affecting the atomization in the diffusion flame was carried out (flow rates and composition of gases, observation height). In the second part, concentrations of individual reagents used (nitric acid, sodium borohydride, Triton X-100, Antifoam B, sodium diethyldithiocarbamate) were optimized. The positive effect of the reaction modifiers was demonstrated, especially that of sodium diethyldithiocarbamate, which lead to a tenfold increase in the sensitivity. The limits of detection and limits of quantification for the wavelength 244,8 nm were 0,25 mg dm-3 and 0,67 mg dm-3, respectively. The repeatability for this method for the concentration 5 mg dm-3 was 2,8 %. Key words: palladium, chemical generation of volatile species, atomic absorption spectrometry
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Preconcentration of hydride forming elements in quartz trap in connection with ICP-MS
Kašpar, Miroslav ; Matoušek, Tomáš (advisor) ; Rychlovský, Petr (referee)
Charles Uviversity in Prague Faculty of Science Department of Analytical Chemistry Student: Miroslav Kašpar Supervisor: RNDr. Tomáš Matoušek, Ph.D. Name of Thesis: Preconcentration of hydride forming elements in quartz trap with ICP-MS detection The aim of this thesis are pilot experiments employing quartz trap (QT) for preconcentration of hydride forming elements and their subsequent detection by inductively coupled plasma mass spectrometry (HG-QT-ICP-MS). Arsenic and antimony were chosen as model analytes. Preconcentration efficiency on quartz surface was studied in a trap, which was integrated into an interface between spray chamber and plasma torch. We have identified a critical loss of analyte during transportation, instability of the plasma due to sudden change of gas composition, poor repeatability and very quick release of Sb from the trap resulting in difficult quantification of Sb signal. Despite the efforts to resolve these experimental problems, so far we were unable to achieve improvements in analytical parameters compared to standard analytical methods. Keywords: Preconcentration, quartz trap, mass spectrometry with inductively coupled plasma, hydride generation, arsenic, antimony
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Trace speciation analysis of arsenic in beverages
Fajgarová, Aneta ; Matoušek, Tomáš (advisor) ; Spěváčková, Věra (referee)
The aim of this bachelor thesis was to determine the toxicologically important arsenic species in beverages (beer, wine and apple juice) with minimal sample preparation. Determination of arsenic species was performed by selective hydride generation of arsenic hydrides with cryogenic collection under liquid nitrogen and detection by atomic absorption spectrometry. In all the samples only inorganic arsenic was found, methyl substituted species were below the limit of detection. The method is suitable for speciation analysis of arsenic in beverages. Detection limits are low enough, the determination is not influenced by the sample matrix. The results were also in good agreement with the determination of total arsenic after mineralization by ICP-MS. Since there is no specified maximum arsenic content in beverages, measured concentrations were compared with the limit for drinking water (10 μg l−1 ). All samples were under this limit, except for one sample of apple juice, which arsenic content was about twice higher. Key words speciation analysis, atomic absorption spektrometry, hydride generation, arsenic, beverages
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