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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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Se-Metabolism inside the mammalian organism fed Se-supplemented Brassica napus forage
Žíla, Ondřej ; Čadková, Zuzana (advisor) ; Václav, Václav (referee)
The aim of the thesis was to determine whether the individual Se-speciation in the mammalian organism are affected by the form of received selenium. Selenium is an essential micronutrient important for humans and animals. It plays an important role in the antioxidant protection of the organism and in the conversion of thyroid hormones. In our experiment the laboratory Wistar rats were divided into three groups. Each group had a different diet. The rats were fed with selenium in the form of soy, sodium selenite and extracted rapeseed meal. Urine samples were regularly collected during the four-week experiment and in the end of the feeding study, the blood serum was also collected. The total selenium content was measured by ICP-MS, while the individual Se-speciation in urine and serum by HPLC coupled with ICP-MS. In the urine the identified speciation were methylselenocystein (MeSeCys), trimethylselenium (TMSe) and selenosugar 1 and 3. In the blood serum the measured speciation were TMSe, selenite, selenate and selenosugar 1. For the group fed with sodium selenite the measured values in the urine were generally higher, this might be due to a higher overall intake and also an inorganic form of selenium with a lower absorbency. Groups that received selenium from plant sources took in several Se-compounds and the total measured content of Se-speciation and secretion dynamics were not significantly different. Additionally speciation of selenosugar 2 was measured for the group fed with rapeseed meals, which in the other groups did not appear. When receiving selenium from plant sources the biotransformation in the mammalian organism differs in comparison to receiving selenium from mineral salts. The initial hypothesis that Se-speciation is influenced by the form of selenium administered in the diet was confirm by our results. Since the group fed rapeseed showed similar results as the group fed a standard feed with soy, the extracted rapeseed meal could serve as a good source in livestock nutrition.
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