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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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Determination of selected trace elements in cosmetic products using solid sampling GF-AAS
Migašová, Michaela ; Petry-Podgórska, Inga (advisor) ; Červený, Václav (referee)
U N IV E R Z IT A K A R LO V A P ř í r o d o v ě d e c k á f a k u l t a Studijní program: Klinická a toxikologická analýza Michaela Migašová STANOVENÍ VYBRANÝCH STOPOVÝCH PRVKŮ V KOSMETICKÝCH VÝROBCÍCH POMOCÍ SOLID SAMPLING GF-AAS Determination of selected trace elements in cosmetic products using solid sampling GF-AAS B a k a l á ř s k á p r á c e Vedoucí bakalářské práce: Dr. Inga Petry-Podgórska Praha, 2017 Prohlášení Prohlašuji, že jsem tuto závěrečnou práci zpracovala samostatně, a že jsem uvedla všechny použité informační zdroje a literaturu. Tato práce, ani její podstatná část, nebyla předložena k získání jiného nebo stejného akademického titulu. V Praze, 28. srpna 2017 ……………… podpis Poděkování Chtěla bych nejvíce poděkovat mé školitelce Dr. Inze Petry-Podgórske za neskutečnou trpělivost a čas, který mi během měření věnovala a za její cenné rady, které mi poskytla. Dále bych chtěla poděkovat panu RNDr. Jakubovi Hraníčkovi, Ph.D. a RNDr. Stanislavu Musilovi, Ph.D. za pomoc při komplikacích s přístrojem. Poděkování také patří mým rodičům za možnost studia na vysoké škole. Abstrakt Anorganická barviva jsou využívána při výrobě barevných laků na nehty. Pigmenty jsou nejčastěji složeny ze sloučenin přechodných kovů. Úkolem této bakalářské práce byla optimalizace podmínek pro stanovení olova ve vybraných...
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HPLC determination of gallic acid as a possible product of enzymatic reaction of shikimic acid, NADP+ and SDH.
Smolejová, Jana ; Červený, Václav (advisor) ; Nesměrák, Karel (referee)
This diploma thesis deals with the development of an HPLC method for the determination of selected compounds participating in enzymatic reaction leading to the formation of gallic acid. The analysed reaction mixture contains the following reagents: shikimic acid, NADP+ and shikimatedehydrogenase (SDH) extracted from parsley; the presumed product of the reaction is gallic acid. Two chromatographic methods for the determination of the above mentioned compounds were developed using C18 HPLC column and porous graphitic carbon Hypercarb column. Molecular absorption spectrometric detection in the UV range was used in all measurements. Separation on the C18 column was found particularly suitable for analysing the composition of the end products of the reaction. Because of the NADP+ and shikimic acid peak overlap it is necessary to observe absorbance at 212 and 260 nm. Shikimic acid and NADP+ can be quantified due to the fact that shikimic acid does not absorb at 260 nm while NADP+ absorb radiation at both wavelengths. Separation via Hypercarb column was found particularly suitable for analysing the process of the reaction; additional products or intermediates can be seen in chromatograms compared to the C18 method. Determination with Hypercarb column is characterized by higher sensitivity and lower limit...
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Synthesis and separation of arsenic-glutathione complexes
Balcárová, Barbora ; Petry-Podgórska, Inga (advisor) ; Červený, Václav (referee)
The arsenic-glutathione complexes are very unstable in solution and tend to decompose during separation in liquid chromatography. The aim of this work was to develop a relatively fast method of the synthesis and storage conditions for the arsenic-glutathione complexes. The thesis is focused on synthesis, stability in-solution and separation of arsenicglutathione complexes. The synthesis was carried out in solution of 2 mM TCEP (tris(2carboxyethyl)phosphine) in water and with excess of the glutathione. Solutions of 20 ppb arsenic-complexes were consecutively measured after 1h, 2h, 3h, 4h and 24 hours of synthesis. The results confirmed stability of the arsenic-complexes in the reaction mixtures over 24 h. The arsenic-glutathione complexes were separated using a reversed phase high performance liquid chromatography (RP-HPLC) coupled with inductively coupled plasma - mass spectrometry (ICP-MS). The chromatographic method was developed using Aeris widepore 3.6u XB-C18 250x2.10mm column. Isocratic and gradient elutions were compared using several compositions of mobile phases and time of the separation. Methods were tested using samples of synthesized arsenic-glutathione complex (DMAs(GS)). An application of the isocratic elution enabled elimination of time needed for the separation and conditioning of...
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