National Repository of Grey Literature 149 records found  beginprevious61 - 70nextend  jump to record: Search took 0.00 seconds. 
Development of a UHPLC-MS/MS method for determination of rivaroxaban in rat serum
Plášilová, Denisa ; Kozlík, Petr (advisor) ; Hraníček, Jakub (referee)
This bachelor thesis is focused on development of a specific UHPLC-MS/MS method for the determination of rivaroxaban in rat serum. At first, the setting of the mass spectrometer was optimized. Suitable MRM transitions were found for rivaroxaban and its isotopically labeled internal standard. For rivaroxaban was found the MRM transition 436.1 → 145.05 with optimal energy levels Q1 = -12.0 V; CE = -30.0 V; Q2 = -27.0 V. For rivaroxaban D4 was found the MRM transition 440.1 → 145.0 with optimal energy levels Q1 = -22.0 V; CE = -31.0 V; Q2 = -25.0 V. The ion source setting parameters were as follows: nebulizing gas flow 3 l/min; heating gas flow 10 l/min; interface temperature 300 řC; desolvation temperature 526 řC; DL temperature 250 řC; heat block temperature 400 řC; drying gas flow 10 l/min. The optimal chromatographic method was as follows: A Poroshell 120 SB AQ, 100 × 2.1 mm, 2.6 µm (Agilent) chromatographic column; the mobile phase consisted of acetonitrile with the addition of 0.1% formic acid (A) and distilled water with the addition of 0.1% formic acid (B); flow rate of the mobile phase 0.5 ml/min; gradient elution (time: 0-1-2-3.5-4-6.5 min; A: 20-20-80-80-20-20 % v/v); autosampler temperature 15 řC; column temperature 40 řC; time of analysis 6.5 minutes; injection volume 2 µl. The optimized...
Interferences in determination of antimony by UV-photochemical generation of volatile compounds and atomic fluorescence spectrometry
Kračmarová, Aneta ; Červený, Václav (advisor) ; Hraníček, Jakub (referee)
This work is focused on the study of interferents of selected elements during UV-photochemical generation of volatile antimony compounds. The interferents included transition metals, halides, hydride-forming elements and salts of mineral acids. Detection was performed by atomic fluorescence spectrometry. Some of the tested added substances proved to be potential reaction modifiers; in their presence, an increase in responses was observed. The best results were obtained using Fe3+ for the determination of Sb3+ and SO4 2- had the best results for the determination of Sb5+ . The largest interferent, i.e. the substance causing the most significant decrease in signal, was for both antimony ions Se4+ .
Determination of sodium and potassium in honey samples by atomic absorption spectrometry
Venclová, Veronika ; Hraníček, Jakub (advisor) ; Šíma, Jan (referee)
This bachelor thesis was focused on the determination of sodium and potassium in honey samples by atomic absorption spectrometry with a flame atomization technique. An acetylene-air flame was used. Prior to the analysis of the honey samples, the optimal working parameters of the used method were found. The optimized parameters were: the height of the beam above the burner, the flow rate of acetylene, and the burner's horizontal position. Under the optimal conditions, the basic characteristics of the determination of sodium and potassium were studied. Sodium and potassium concentrations in the honey samples were determined under optimal conditions. A total number of 27 honey samples were analyzed. The sodium content ranged from 0.880 to 25.3 mg/kg. The potassium content was in the range of 223 - 2750 mg/kg. In the end, the measured concentrations of honey samples originating from the Czech Republic were compared with the foreign studies. Keywords Potassium, sodium, honey, atomic absorption spectrometry, flame spectrometry
Determination of selected metals in tea samples and bag materials
Hlávka, Jan ; Nováková, Eliška (advisor) ; Hraníček, Jakub (referee)
This bachelor thesis is dealing with determination of antimony in materials modern pyramid-shape tea bags. Possible presence of antimony in these materials, e.g. polyethylene terephthalate (PET) or mixed materials, is caused by using it like catalyst in production of polyethylene terphthalete. The goal of this bachelor thesis is the verification of hypothesis, that antimony is present in materials of pyramide tea bags and that it is released to consumed drink, if higher concentration of antimony is present, and that it could pose a health risk to the consumer. At the same time, I studied if tea leaves are contaminated by other toxic elements, from which some can result from intesive agricultural production. They can be used as pesticides or be presnet in industrial fertilizers. In this thesis I examined the content of As, Cd, Cu, Sb and Zn in tea leaves sold in pyramide bags. These pyramide bags were purchased in local supermarkets and shops. The content of Sb in bags was determined too. The applied method included the decomposition of samples in a microwave decomposition device and analysis of the composition of the resulting solution by the ICP-MS method. Determined contents of the investigated elements were expressed like content of element in the sample in dry mass and the results were compared...
Determination of calcium, copper, and lead in leaves by inductively coupled plasma-mass spectrometry
Plecháč, Matěj ; Hraníček, Jakub (advisor) ; Červený, Václav (referee)
V této práci byly stanovovány koncentrace vápníku, mědi a olova ve vzorcích listů pomocí metody ICP-MS. Vzorkovaný materiál pocházel z různých míst České republiky a jednalo se o listy různých druhů stromů. Vzorky listů byly sušeny a poté rozloženy v mikrovlnném rozkladném zařízení za přítomnosti koncentrované kyseliny dusičné. Ve výsledcích bylo prokázáno, že koncentrace kovů se liší podle lokality sběru a v rámci jedné lokality byly různé u listů jednotlivých rostlinných druhů. Stanovené koncentrace vápníku se pohybovaly v rozmezí 5,6 - 30 mg/g a její průměrná koncentrace byla 14 mg/g. Koncentrace mědi byla v rozmezí 4,3 - 18 µg/g a její průměrná koncentrace byla 9,91 µg/g. Koncentrace olova byla v rozmezí 0,19 - 3,2 µg/g a jeho průměrná koncentrace byla 0,79 µg/g. V této práci bylo také ověřeno, že zvolený postup přípravy vzorků byl vhodný pro analýzu vzorků listů na ICP-MS, a že metoda ICP-MS byla díky nízkým limitům detekce vhodná pro stanovení koncentrací všech vybraných kovů.
Synthesis of novel compounds as potential radioprotectives
Živná, Natálie ; Hraníček, Jakub (advisor) ; Górecki, Lukáš (referee)
Harmful substances polluting the environment, including ionizing radiation, and an unhealthy lifestyle are responsible for the increased incidence of cancer. The projected outlook for the next ten to twenty years suggests an increase of 63% in newly diagnosed cases of cancer annually. Radiotherapy is an important component of cancer treatment, given approximately to 50% of all cancer patients. Despite ongoing advances in the methods of radiotherapy, quality of life continues to be lowered as a result of the radiation treatment. Novel strategies towards improvement need to be adapted, such as the use of radioprotective substances. The goal of this thesis is to synthesize novel radioprotective agents based on the 1-(2- hydroxyethyl)piperazine moiety targeting the intrinsic apoptotic pathway, therefore protecting healthy tissue from ionizing radiation.
Study of properties of UV-photochemical generation of volatile compounds od antimony
Adámková, Dominika ; Červený, Václav (advisor) ; Hraníček, Jakub (referee)
The master thesis deals with comparison of atomic fluorescence spektrometry and high resolution continuum source atomic absorption spektrometry for three methods generation of volatile compounds Antimony. In both methods of atomic antimony detection, it compares the most common chemical generation of volatile compounds (hydrides) with two alternative methods - electrochemical and UV - photochemical. The values of performance parameters for the determination of Sb(III) and Sb(V) were determined for all the above combinations. In the case of chemical generation, a surprisingly almost four times higher limit of detection of Sb(III) was found in connection with AFS detection than AAS detection. The final part was devoted to UV - photochemical vapor generation, with AAS detection for Sb(III) reaching limit of detection 4,96 ppb, for Sb(V) 8,63 ppb. Although UV - photochemical generation of volatile antimony compounds did not reach such performance parameters as chemical or electrochemical generation, it was observed that the sensitivity of antimony determination increased greatly when introducing oxygen into the apparatus. The interference study also found a significant positive effect of Fe(II) on the generation efficiency, and this modification partially persisted without further introduction of these...
Analysis of fruits and vegetables extracts by atomic spectrometry methods
Petráňová, Karolína ; Hraníček, Jakub (advisor) ; Kozlík, Petr (referee)
EN The aim of this thesis was to determine selected elements - chromium, manganese, copper, iron and zinc - in fruit and vegetable extracts. The method used for measurement was atomic absorption spectrometry with flame atomization. First, the optimal conditions for the measurement were found. Then the basic characteristics of the determination of each element under optimal conditions were determined. The determined optimal conditions were used in the analysis of real samples of extracts. The samples were appropriately diluted before measurement. The content of all 4 selected elements was determined in all 36 extracts from fruits and vegetables. All results were provided with statistical evaluation.

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