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Determination of zinc in food supplements
Nedorostová, Helena ; Hraníček, Jakub (advisor) ; Šíma, Jan (referee)
- 1 - Abstrakt Tato bakalářská práce je zaměřena na stanovení zinku (zinečnatých iontů) v potravinových doplňcích pomocí atomové absorpční spektrometrie. Součástí práce je také porovnání mezí detekce dvou odlišných atomových spektrometrů. Cílem práce bylo zjistit optimální podmínky a vliv interferencí na stanovení zinku, nalézt vhodnou metodu pro převedení vzorku do roztoku, a také porovnat meze detekce u použitých přístrojů. Optimalizovanými parametry byla výška paprsku nad hranou hořáku, průtoková rychlost acetylenu, otočení hořáku, šířka spektrálního intervalu, typ plamene. Převedení pevného vzorku do roztoku bylo provedeno ve vodě za laboratorní i zvýšené teploty, v kyselině dusičné nebo kyselině dusičné s přídavkem peroxidu vodíku, též za zvýšené teploty. Analyzovány byly tyto potravinové doplňky: Centrum od A až po železo, Walmark- vápník, hořčík, zinek, Spektrum 50+, Calibrum 50 plus, Supradyn Energy Complex. Množství zinku v potravinových doplňcích bylo stanoveno na spektrometru GBC 933 AA v kolmém uspořádání. K porovnání meze detekce byly použity přístroje GBC 933 AA s výbojkou s dutou katodou a ContrAA 700 s xenonovou výbojkou. U obou přístrojů byl pro experiment použit plamen obsahující acetylen-vzduch. Pro stanovení zinku byla pomocí standardních roztoků vytvořena kalibrační křivka, z níž byly...
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Determination of zinc, cadmium and nickel in leaves by inductively coupled plasma-mass spectrometry
Plodík, Michal ; Hraníček, Jakub (advisor) ; Červený, Václav (referee)
Práce je zaměřena na stanovení těžkých kovů (zinku, kadmia a niklu) v listech různých druhů stromů. Vzorky byly odebrány z různých lokalit na území České republiky. Pro analýzu byla použita hmotnostní spektrometrie s indukčně vázaným plazmatem, která je dostatečně citlivá pro předpokládané nízké koncentrace vybraných kovů. Pro stanovení koncentrace byla klíčová příprava vzorků pro mikrovlnný rozklad v koncentrované kyselině dusičné. Naměřené koncentrace sledovaných kovů se lišily nejen mezi lokalitami a jednotlivými rostlinnými druhy, ale také v rámci jedné lokality. Použitá metoda ICP-MS prokázala dostatečnou citlivost i u prvků s přirozeně nízkou koncentrací v životním prostředí, což bylo v této práci kadmium.
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Use of pollution indices for evaluation of soil contamination
Čmelíková, Dorota ; Pavlovský, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
This thesis focuses on heavy metal contamination of soil and the use of pollution indices for its evaluation. Two regions were selected for assessment and comparison. The chosen heavy metals were mercury, zinc, copper, lead and cadmium. These heavy metals were analysed in 15 samples from Kyjov nad 15 samples from Ostrava. Methods of analysis were AMA-254 and FAAS. The established concentrations were used to calculate pollution indices and for health risk assessment. Pollution in Kyjov was assessed as low to medium without any health risks. Ostrava region was assessed as moderately to highly polluted with a low health risk, especially for children.
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Plant bioindicators of heavy metals
Pecinová, Eliška ; Doležalová Weissmannová, Helena (referee) ; Komendová, Renata (advisor)
The urban areas are exposed to high risk of contamination, and some of the plant species can indicate this contamination. For this study, plants which can accumulate heavy metals and meet the requirements for bioindicators were chosen. Lichens, moss, birch, linden, and yew were chosen as bioindicators. Plant samples were collected from the specified localities in Brno, both with and without heavy traffic, then analysed by atomic absorption spectrometry for the contents of Cd, Cu, Hg, Pb and Zn. Copper (max 47,7 mgkg-1) and zinc (max 200 mgkg-1) were detected in concentrations higher than the lower border of potential phytotoxic concentrations. Lichens and mosses were proved as the best bioindicators for most of the contaminants (Cu, Hg, Pb), except for zinc, which was indicated by birch. Linden wasn’t suitable for biomonitoring. The result concentrations in bioindicators were very variable among localities, without visible effect of traffic load, which implies other factors, which outweighed factors of contamination from the nearby traffic.
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The study of vertical mobility of heavy metals and their transfer to mushrooms
Jurnečka, Roman ; Doležalová Weissmannová, Helena (referee) ; Komendová, Renata (advisor)
This bachelor thesis deals with the issue of contamination of forest soils and edible mushrooms with lead, cadmium, copper and zinc in the Jeseníky Mountains, specifically in the Domašov and Vápenná forests. Sampling took place at 12 localities, divided into spruce and beech stands. Atomic absorption spectrometry AAS ContrAA 800D was chosen to determine the content of selected heavy metals. Based on the measured values of the concentrations of the studied metals and other soil properties, dependences were created to determine the vertical mobility of selected metals in the soil profile. Vertical mobility depends on the physico-chemical properties of the soil (pH, C and S content). The dependence of the content of selected heavy metals in the soil on the pH value of the soil was found. In the case of lead, the sorption capacity of the soil organic component was confirmed. The risk and above-limit content of Pb, Cd and Cu was found on the yellow-boletus mushroom. Cadmium shows the highest bioavailability. Lead was evaluated as the element with the lowest mobility.
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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...
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The impact of synthetic chelators from the group of 4-acylpyrazole-5-ones on alcohol dehydrogenase
Sobolová, Zuzana ; Mladěnka, Přemysl (advisor) ; Jirkovský, Eduard (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Zuzana Sobolová Supervisor: Prof. Přemysl Mladěnka, Pharm.D., Ph.D. Consultant: Marcel Hrubša, MS.c. Title of diploma thesis: The impact of synthetic chelators from the group of 4-acylpyrazole-5-ones on alcohol dehydrogenase Inhibitors of alcohol dehydrogenase play a key role in the treatment of poisoning caused by methanol, ethanol, ethylene glycol, and their toxic metabolites. Such treatment can therefore be considered as life-saving. In clinical practice, a single substance, fomepizole, is used. This thesis is aimed at investigation of the effect of eleven experimental chelators from the 4- acylpyrazol-5-ones group on equine and yeast alcohol dehydrogenases, and the possible definition of structural features that would be the most suitable for interaction with this enzyme. Due to the ability of these substances to chelate zinc ions, it is believed that they could inhibit an enzyme that has a zinc molecule in the structure. The measurement itself is based on principle of increase in absorbance during the enzymatic reaction, which is caused by the formation of NADH. This measurement is relatively simple, efficient and, due to used kinetic method, also less susceptible to be affected by...
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Influence of zinc loss during the sintering on permeability/inductance of ferrite ceramics
Kvapilová, Vendula ; Ptáček, Petr (referee) ; Šoukal, František (advisor)
The diploma thesis is focused on the investigation of the effect of zinc release during ferritic sintering on the permeability/inductance of ferrite ceramics. The theoretical part deals with the position of ferrites among other ceramic materials. It describes the basic characteristics of ferrites, their crystal structure and finally the problems that are directly related to their production and which fundamentally affect the magnetic properties of ferrites. In the second part of the work, the influence of the temperature and time of sintering and the position of the cores in the furnace during firing on the loss of zinc from the sample and subsequently on the electromagnetic properties of the prepared test specimens from industrial raw material mixtures was investigated. These are initial experiments, which will be followed by further research aimed at eliminating the problem of zinc loss in the production of Mn-Zn ferrites.
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Structure and mechanical properties of magnesium materials prepared by SPS
Pleskalová, Kateřina ; Hutařová, Simona (referee) ; Doležal, Pavel (advisor)
This diploma thesis deals with the processing of the magnesium-based powder materials with the addition of zinc by the spark plasma sintering. The aim of this thesis is to evaluate influence of sintering parameters and zinc content on the microstructure and mechanical properties of the material. First part of the thesis is literary research which is divided into two main chapters. The first chapter describes magnesium-based materials and mentions their use as biomaterials. The second chapter discusses powder metallurgy, specifically magnesium powders and spark plasma sintering. In the experimental part the powders were sintered at temperatures 300 °C and 400 °C and an analysis was performed using optical microscope, scanning electron microscope, then also EDS analysis and hardness, microhardness and three-point bending tests were performed. An increase in hardness was observed with increasing zinc content and with increasing sintering temperature. The flexural strength was higher for materials sintered at a temperature of 400 ° C.
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Biodegradable bones implants based on iron
Hrabovský, Jan ; Zatloukal, Miroslav (referee) ; Sedlaříková, Marie (advisor)
This work deals with a current topic, which are biodegradable bone implants. These implants seem to be a suitable candidate for temporary fixations, with their gradual decomposition. An important parameter is not only the mechanical properties so that the material can withstand the load, but above all the corrosion properties and the degradation process. This work introduces the physiology of bone, trace elements and also describes current trends in the field of implants. The last part is a theoretical introduction to cross-stage processes. The practical part is focused on the preparation of iron-based samples with various dopants, subsequent annealing and analysis.
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