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Extraction of Selected Mercury Compounds from Real Samples for Speciation Analysis Employing RP-HPLC-UV-CVG-QTAAS
Kolorosová, Alžběta ; Červený, Václav (advisor) ; Kratzer, Jan (referee)
The extraction of mercury species (methylmercury, ethylmercury, phenylmercury and inorganic mercury(II)) from fish tissue, its determination by reverse phase HPLC, UV-photochemical generation of cold vapour, and detection by atomic absorption spectrometry is described in this work. Various extraction agents and digestion methods were compared in order to find the best alternative. The mixture of 6.25% tetramethylammonium hydroxide and 0.05 mol·l-1 hydrochloride acid was chosen as the best extraction agent. In addition to the high extraction efficiency, the solution involved positively not only UV-photochemical generation, but also separation of observed species. On the contrary, the poor repeatability was achieved with the microwave-assisted digestion due to the proved sorption of mercury species on the Teflon vessels. Therefore, the extraction by high temperature (50-60 řC) in glass bottles was preferred. The results of the determination of the mercury species after the extraction from the real samples were compared to the outcomes obtained by AMA 254. The proposed extraction technique together with the RP-HPLC-UV-CVG-QTAAS is suitable for the speciation analysis of mercury.
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Speciation analysis of arsenic-glutathione complexes by ion-pairing HPLC-ICP-MS
Zušťáková, Veronika ; Matoušek, Tomáš (advisor) ; Červený, Václav (referee)
The thesis has focused on the separation of arsenic-glutathione species using ion-pairing high performance liquid chromatography with detection by inductively coupled plasma mass spectrometry. Species were separated on chromatographic column Prodigy ODS (3) using an aqueous mobile phase containing 4.7mM tetrabutylammonium hydroxide (TBAH), 2mM malonic acid and 4% methanol at pH 5.85 in the isocratic mode. Simple arsenic species - arsenite (iAsIII), arsenate (iAsV) monomethylarsenic acid (MAsIII), monomethylarsenous acid (MAsV), dimethylarsenic acid (DMAsIII) and dimethylarsenous acid (DMAsV), which served as arsenic standards to determine retention times, were successfully separated under these conditions. Arsenic-glutathione complexes As(GS)3, MAs(GS)2 and DMAs (GS) were not successfully separated. These complexes provided peaks of simple arsenic species. Peak broadening was observed in the first analysis of As(GS)3 and MAs(GS)2 complexes, which disappeared in subsequent analyses. This broadening probably represents a residual of glutathion complex which disintegrated to single species. Powered by TCPDF (www.tcpdf.org)
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Optimization of generation and atomization of arsines for speciation analysis by atomic fluorescence spectrometry
Marschner, Karel ; Dědina, Jiří (advisor) ; Komárek, Josef (referee)
Speciation analysis of arsenic based on selective hydride generation and detection by atomic fluorescence spectrometry have been studied in this work. It was found that under optimum conditions of atomization in the flame in gas shield atomizer, sensitivity was approximately twice higher and detection limit was about four times lower compared to miniature diffusion flame, which is a standard atomizer for atomic fluorescence spectrometry. The conditions to generate hydrides from both inorganic forms of the arsenic, i.e. from arsenite and arsenate, with the same efficiency have been found in the batch arrangement, by using 1 mol dm-3 hydrochlorid acid and 1% solution of tetrahydridoborate. To determine only trivalent form, TRIS buffer at pH 6.00 was used together with 1% sodium tetrahydridoborate. The detection limits found for inorganic arsenic, i.e. for arsenite and arsenate, respectively, were 15 ng dm-3 and 9 ng dm-3 . It was found that in the batch arrangement under these conditions it is possible to generate corresponding hydrides methylarsonate and dimethylarsonate with the same efficiency as from the inorganic form. Finally, it was found when slightly changing the gas-liquid separator design in order to introduce the mixture of tetrahydridoborate with hydrochloric acid to the bottom of the...
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Contribution to optimization of parameters of speciation analysis of As based on selective hydride generation in direct transfer mode and detection by atomic absorption spectrometry
Vyvadilová, Tereza ; Dědina, Jiří (advisor) ; Korunová, Vlasta (referee)
The presented thesis deals with optimization of parameters speciation analysis based on a selective hydride generation in a direct transfer mode of hydrides and on-line atomization in an atomic absorption spectrometer. In the first part of the thesis processes during generation were investigated. Important indicator of a reactions taking place in a generator is volume of hydrogen (created by decomposition of NaBH4) which is subsequently introduced to the atomizer. In this part of the thesis a new approach to determine a flow rate of hydrogen delivered to the atomizator was developed. An influence of relevant paremeters of the atomizers and atomic absorption spectrometers on basic analytical characteristics of arsenic determination based on hydride generation was performed in the second part. Three atomic absorption spectrometers were used and three sources of radiation were compared. The most important analytic characteristic was the limit of detection which is influenced by standard deviation of measurement values of blank samples and by sensitivity. The best values of the limit of detection were achieved with electrodeless discharge lamps. Key words: hydride generation, arsenic, speciation analysis, atomic absorption spectrometry
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Speciation Analysis of Selected Mercury Compounds Using HPLC, UV-Photochemical Cold Mercury Vapor Generation and its AAS Detection
Linhart, Ondřej ; Červený, Václav (advisor) ; Spěváčková, Věra (referee)
The mercury occurs in the environment in a variety of forms. Mercury compounds can be found in the soil, atmosphere, water and living organisms. Although some of the mercury substances are very toxic, they are often used in various sectors of industry, agriculture and medicine. Mercury compounds differ in their toxicity, so it is necessary to do speciation analysis. The aim of this diploma thesis was to develop and validate a new analytical method for the determination of mercury compounds in different samples. This method involves the combination of high performance liquid chromatography, UV-photochemical cold vapor mercury generation and atomic absorption spectrometry. Effective separation of mercury(II), methylmercury(I), ethylmercury(I) and phenylmercury(I) ions and subsequent comparable efficient of mercury cold vapor generation from all of forms was achieved using these techniques. The reached detection limits were 8 µg l-1 , 31 µg l-1 , 16 µg l-1 and 38 µg l-1 . At the end of experimental work, the proposed method of RP-HPLC-UV-CVG- QTAAS was used for the determination of mercury compounds in real samples (fish tissue and water samples: Labe, Vltava and tap water) and in certified reference materials (DORM-3 and DOLT-4). Several methods for extraction of mercury species from solid samples...
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Separation of toxicologically relevant arsenic species for speciation analysis by RP-HPLC-ICP-MS
Kanásová, Mária ; Matoušek, Tomáš (advisor) ; Červený, Václav (referee)
The thesis is mapping possibilities of separation of toxicologically relevant arsenic species complexed with peptides by reversed-phase high-performance liquid chromatography-inductively coupled plasma mass spectrometry (RP-HPLC-ICP-MS). The C18 chromatography column and gradient elution of the mobile phase (0,1% formic acid with gradient of acetonitrile) was used. At these conditions the separation of simple arsenic species - arsenite (As(III)), arsenate (As(V)), monomethylarsenic acid (MA(III)), monomethylarsenous acid (MA(V)), dimethylarsenic acid (DMA(III)) and dimethylarsenous acid (DMA(V)) was not successful. However, separation of arsenic- -glutathione complexes - arsenic triglutathione (ATG), methylarsenic diglutathione (MADG) and dimethylarsenic glutathione (DMAG) was obtained. Several chromatographic peaks were observed at higher concentration of acetonitrile in mobile phase. The analysis of two in vitro methylation mixtures was also examined. Mixtures contained arsenite (As(III)), S-(5'-adenosyl)methionine chloride (SAM), tris(2-carboxyethyl)phosphine (TCEP) and arsenic(3+)methyltrasferase enzyme (AS3MT) probably participating in human arsenic metabolism. Second mixture also included glutathione (GSH). Several chromatographic peaks of complex species were obtained by analyzing these...
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Contributions to Volatile Compound Generation of Arsenic, Silver and Gold by Tetrahydroborate Reaction for Atomic Absorption Spectrometry
Musil, Stanislav ; Rychlovský, Petr (advisor) ; Kanický, Viktor (referee) ; Spěváčková, Věra (referee)
(EN) The presented dissertation thesis summarizes the results contained in five original research papers that were published in prestigious international scientific journals in the field of analytical chemistry and atomic spectrometry. It is devoted to the method of generation of volatile compounds using a tetrahydroborate reaction and detection in a quartz multiatomizer by atomic absorption spectrometry. The thesis can be divided into two thematic parts - speciation analysis of arsenic based on hydride generation technique with collection and separation in a cryogenic trap and generation of volatile species of transition metals. In the first thematic part pre-reduction of pentavalent inorganic and methylated arsenicals has been studied. A simple setup for on-line pre-reduction employing thioglycolic acid as a fast pre-reductant has been developed, connected with a current hydride generator and applied/verified to oxidation state specific arsenic speciation analysis of human urine samples. In the same method the possibility of drying the gaseous phase from water vapor has been investigated to avoid incidental blocking the cryogenic trap by frozen water and to decrease fluctuations of signal baseline. Pronounced losses of methylated species have been discovered on Nafion tube dryer currently used in...
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The Speciation Analysis of the Toxicological Important Forms of the Arsenic in Urban Particulate Matter Samples with the Detection QF-AAS
Jelínek, Petr ; Rychlovský, Petr (advisor) ; Červený, Václav (referee)
The topic of this diploma thesis was the speciation analysis of the toxicological important forms of the arsenic in urban particulate matter samples. The detection technique used in this work was atomic absorption spectrometry with quartz atomizer. Acetic acid, ammonium acetate, hydroxylamine, potassium hydroxide and sodium carbonate are recommended leaching agents for extraction of metals from urban particulate matter samples. Results of the presenting work are following: Acidic extraction reagents can be not recommended for the speciation analysis of the arsenic, because these reagents lower sensitivity of the determination of As3+ and As5+ too and destroy the quartz atomizer. Alkaline extraction reagents don't lower sensitivity of the determination of As3+ and these reagents don't destroy the atomizer, but lower sensitivity of the determination of As5+ was obtained. Recommended reagents aren't useful for extraction of the metals from urban particulate matter samples for the speciation analysis.
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Speciation analysis of chromium in particulate matter of urban dust
Rybínová, Marcela ; Hraníček, Jakub (referee) ; Rychlovský, Petr (advisor)
Anion-exchange chromatography with inductively coupled plasma - atomic emission spectrometry (ICP-AES) has been used for the speciation of chromium (Cr). Chromium speciation has attracted attention because of the different toxicity, Cr(III) is relatively non-toxic and Cr(VI) has been classified as a human carcinogen. The aim of the present study was to develop simple method for the speciation analysis of Cr (Cr(III) and Cr(VI)) in particulate matter of urban dust. A combination of 2% KOH + 3% Na2CO3 has been chosen as the optimal reagent for the extraction of chromium from particular matter. It was found that there was no conversion of Cr(VI) into Cr(III). The effect of separation parameters such as acidity of mobile phase was also studied. The detection limit for Cr(VI) was about 12 ng.ml-1 . Results for the determination of Cr(VI) were confirmed by the analysis of standard reference material (BCR CRM 545, Cr(VI) in welding dust loaded on a filter) with good agreement between certified (40,16 ± 0,60 μg.g-1 ) and found (37,83 ± 1,14 μg.g-1 ) values.
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