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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 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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