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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 manganese in food supplements by atomic absorption spectrometry
Melicharová, Zuzana ; Hraníček, Jakub (advisor) ; Šíma, Jan (referee)
EN The main content of this thesis was the determination of manganese in the form of manganese ions in food supplements by the atomic absorption spectrometry. It was necessary to find the optimum conditions for this method, to conduct interference studies, to find a suitable way of transferring samples into solution and to determin manganese to achieve this goal. Following parameters were examined in optimalization study: beam height above burner edge, burner horizontal position, acetylene flow rate, torch angle, and spectral interval width. Copper, iron, sodium and calcium ions were investigated as interferents as they were present at the highest concentration in selected food supplements. The conversion of solid samples into solution was carried out in water and nitric acid at a room temperature as well as elevated temperature. These food supplements were selected for analysis: Calibrum 50 Plus, Caltrate Plus, Center A to Iron, DAS Gesunde Plus A-Z Multispectrum, GS Extra Strong Multivitamin, Spectrum 50+ and Supradyn Energy Complex. The manganese assay was performed on a GBC 933 AA spectrophotometer. Standard solutions were measured to determine the detection limit and the limit of determination of the instrument. The detection limit was 0.001 mg/l and the limit of determination was 0.004 mg/l...
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Trace determination of tin by HG-AAS with in-atomizer trapping: method optimization and analytical applications
Průša, Libor ; Hraníček, Jakub (advisor) ; Spěváčková, Věra (referee)
A quartz multiatomizer with its inlet arm modified to serve as a trap (trap and atomizer device) was employed to trap the tin hydride and subsequently to volatilize collected analyte species with atomic absorption spectrometric detection. Generation, atomization and preconcetration conditions were optimized and analytical figures of merit of both on-line atomization as well as preconcentration modes were quantified. Preconcentration efficiency of 95 ± 5 % was found. The detection limits reached were 29 and 143 pg ml-1 Sn, respectively, for 120 second preconcentration period and on-line atomization mode without any preconcentration. The interference extent of other hydride forming elements (As, Se, Sb and Bi) on tin determination was found negligible in both modes of operation. The applicability of the developed preconcentration method was verified by Sn determination in a certified reference material as well as by analysis of real samples. Key words HG-AAS, multiatomizer (multiple microflame quartz tube atomizer), trap and atomizer device, tin determination, stannane, in atomizer trapping, interference study
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