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Determination of Mercury in Hair by Atomic Fluorescence Spectrometry
Šandlová, Petra ; Červený, Václav (advisor) ; Hraníček, Jakub (referee)
The functionality of PS Analytical's Millenium Merlin Satellite external module to the PSA Millenium Excalibur atomic fluorescence spectrometer has been demonstrated on real samples. Hair was selected as real samples. In the first part, several extraction procedures were tested to obtain the highest response. The best results were obtained by the extraction method with TMAH and HCl in FIA-UV-PVG- AFS mode. In the next part, an attempt was made to optimize the conditions for the separation of mercury speciation, namely Hg2+ and MetHg. The optimized parameters were: the percentage of organic component in the mobile phase, the pH of the mobile phase, the flow rate of the added mobile phase per column, and the flow rate of the added 0.050M HCl per column. After this stage, 3 more extraction procedures were tested: extraction using L-cysteine with HCl, extraction using PDTC and extraction using DEDTC. However, none of the extraction procedures was better than the extraction method with TMAH and HCl. Despite the optimization of the method, the speciation of Hg in the hair samples failed because the chromatograms obtained did not match (even in retention times) those obtained for the mixture of standards with the mobile phase extraction reagents. Subsequently, the conditions for the determination of total...
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Determination of cesium in aqueous extracts of cement samples
Straka, Marek ; Hraníček, Jakub (advisor) ; Nováková, Eliška (referee)
Cement is widely used as a solidification material of low and intermediate level radioactive waste containing caesium before shallow land burial. The aim of this thesis was to extract caesium out of seventeen cement samples with six different cement binder compositions, by extraction with deionized water, then determine the amount of caesium in the extracts and look for trends in the extract Cs concentrations with various extraction duration. Cement samples, with stable caesium nuclide, were used to simulate retention of caesium in immobilized radioactive waste. Ten extractions from each sample in total were made with time ranging from 2 to 1032 hours. Atomic absorption spectrometry with flame atomization, using acetylene as fuel and air as oxidant, was used for caesium determination. This method was optimized and the addition of KCl serving as ionization buffer for better results was explored and compared. Keywords Atomic absorption spectrometry, flame atomization, caesium, extraction,
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Elemental analysis of selected types of herbal teas
Adámková, Petra ; Hraníček, Jakub (advisor) ; Šíma, Jan (referee)
In this bachelor thesis the concentrations of magnesium, potassium, manganese, zinc, copper, chromium, cadmium and lead in selected herbal teas and their infusions were determined. Teas from two competing producers on the Czech pharmaceutical market were selected for analysis. The aim of this work was a mutual comparison of selected tea samples in terms of their elemental content. An indicative study of the effect of water temperature and leaching time on the release of elements into the solution during the preparation of the pickle was carried out. The applied method included the decomposition of samples in a microwave device in the presence of concentrated nitric acid and analysis of the composition of the prepared solutions using ICP-MS. The results showed that the element contents differ according to the type of plant and according to the producer. Furthermore, it was proven that the leaching time has a greater influence on the release of elements into the solution than the water temperature. In this work, it was also verified that the ICP-MS method was suitable for determining the concentrations of all selected metals due to low detection limits. Key words Mass spectrometry, inductively coupled plasma, herbal teas, metals, microwave decomposition
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Determination of calcium in food supplements
Hubčuková, Karmelita ; Hraníček, Jakub (advisor) ; Sobotníková, Jana (referee)
Tato bakalářská práce byla zaměřena na stanovení vápníku ve vybraných potravinových doplňcích s využitím plamenové atomové absorpční spektrometrie. Nejdříve byla prováděna optimalizace podmínek s využitím plamene acetylen-vzduch a následně s využitím plamene acetylen-oxid dusný. Optimalizovanými parametry byla výška paprsku nad hranou hořáku, horizontální poloha hořáku, šířka absorpčního prostředí, průtoková rychlost acetylenu a oxidu dusného. Byla sestrojena kalibrační závislost stanovení vápenatých iontů a odpovídající meze detekce a stanovitelnosti. Následně byly vybrané vzorky potravinových doplňků několika způsoby převedeny do roztoku. Vyzkoušeno bylo rozpouštění v deionizované vodě, rozpouštění v koncentrované kyselině dusičné a rozklad pomocí mikrovlnného tlakového zařízení. Experimentálně bylo stanoveno množství vápníku v potravinových doplňcích, které bylo porovnáváno s údaji uvedenými od výrobce. Správnost měření byla ověřena analýzou referenčního materiálu.
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Determination of methanol derivatives in drying oils
Horká, Hana ; Hraníček, Jakub (advisor) ; Janoš, Pavel (referee)
The formation of metal carboxylates is a major problem for historical and contemporary paintings, and therefore understanding the mechanism of their formation is a crucial step for developing appropriate conservation strategies and preserving the world's cultural heritage. The determination of reactive components in drying oils is an important step towards understanding the reaction mechanism. This work is aimed at developing a simple and rapid methodology for HPLC-DAD determination of low molecular weight degradation products of traditional drying oils, namely methanol, formaldehyde and formic acid. In this work, QuEChERS conditions for the extraction of methanol, formaldehyde and formic acid from various oil samples (olive, walnut, poppy and linseed oils) were optimized followed by purification of the samples from the oil matrix using a commercial d-SPE sorbent (Z-Sep/C18) and two nanostructured sorbents, CeO2 and ZrO2.
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Determination of selected elements in coffee samples using ICP-MS method
Švecová, Pavla ; Hraníček, Jakub (advisor) ; Červený, Václav (referee)
EN The main aim of this thesis is focused on the determination of selected elements (manganese, copper, zinc, iron) in trace levels in selected samples of grained and instant coffee. Four samples of grained coffee and one sample of instant coffee were taken for analysis. Firstly, all samples were digested in a microwave digestion system and then analysed by inductively coupled plasma mass spectrometry to determine the concentration of selected elements. Except this, one sample of grained coffee was taken for two additional experiments. The aim of these experiments was to investigate the influence of the extraction time and temperature of water used for extractions, on the element concentrations in liquid phases. The content of elements in the analysed samples shows relatively wide range of values (7.58 - 34.4, 0.21 - 13.6, 1.58 - 5.35 and 12.2 - 55.8 µg/g for manganese, copper, zinc and iron, respectively). Generally, the lowest concentrations of all elements were detected in sample of instant coffee, which cannot be regarded as a valuable source of trace elements for humans. The first additional experiment shows that the concentrations of elements in grained coffee is much higher than in its extractions. With increasing time of extraction, the concentration of elements increased as well (except of...
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Determination of selected heavy metals in samples of great tits feathers by inductively coupled plasma mass spectrometry
Adamová, Simona ; Hraníček, Jakub (advisor) ; Kozlík, Petr (referee)
EN As a result of human activity, a number of polluting substances are released into the environment. Heavy metals are one of the types of these contaminants. Their accumulation in the environment can have a negative impact on living organisms, including humans. For this reason, environment quality monitoring has become an important activity. Great tit (Parus major) can be a suitable bioindicator of the level of environmental contamination by heavy metals, which is acceptable mainly due to its abundance and occurrence in the vicinity of human settlements. This diploma thesis deals with the determination of six selected heavy metals in feather samples of these songbirds from several parts of the Czech Republic and other European countries. High pressure microwave mineralization in the presence of acids was used to prepare the samples. Selected heavy metals were determined using inductively coupled plasma mass spectrometry (ICP-MS) technique, which is also suitable for ultratrace analysis due its very low limits of detection.
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