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Methods for the extraction of selected toxins from solid matrices and their subsequent determination by HPLC/MS
Herman, David ; Zlámalová Gargošová, Helena (referee) ; Čáslavský, Josef (advisor)
This diploma thesis is focused on the analysis of toxins and their extraction from sandyloamy soil. Particularly, saxitoxin and trichothecene mycotoxins deoxynivalenol, HT-2 and T-2 toxins are in the centre of interest of this work. Their occurrence, toxic properties and influence on living organisms are described in theoretical part of this thesis. In next chapters, currently published extraction methods for individual toxins and analytical approaches for their quantitative evaluation are summarized. In experimental part of this thesis, optimized process of sample pretreatment based on extraction of toxins from soil using 1mM HCOONH4 in 84% acetonitrile was proposed as the best option. Simultaneous determination of toxins was performed by liquid chromatography on a CN column (3.0 x 150 mm, 3 m, 100 ) in gradient elution mode. Mass spectrometer with electrospray as ion source and linear ion trap as analyzer was used as detector. Recovery of designed method was over 80% for trichothecene mycotoxins and 51% for saxitoxin.
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Determination of selected perfluoroalkyl compounds in complex matrices
Ondreášová, Klára ; Vávrová, Milada (referee) ; Mgr. Petra Kosubová, Ph.D (advisor)
Diploma work focuses on the determination of selected representatives of perfluoroalkyl substances in complex matrices, particularly, in sewage sludge and feed. In case of sewage sludge, samples were extracted into methanol and three extractions techniques were compared: accelerated Soxhlet, pressurized liquid extraction and Powley method. Powley method showed sufficient efficiency, the lowest matrix effect and minimal background. Perfluorooctane sulfonate was present in all tested samples of sewage sludge (0.74–38.02 ng.g-1). Other detected compounds were perfluorodecanoic acid and perfluorooctanoic acid. Three extraction techniques were tested on feed samples (QuEChERS, fast methanol extraction and Powley method into acetonitrile). Powley method provided the cleanest extracts and showed simultaneously the highest recovery of native perfluoroalkyl substances and the lowest matrix effects. Perfluorooctane sulfonate and perfluorooctanoic acid were rarely present in samples of complete and supplemental feeds, while other perfluoroalkyl substances were found at levels below limit of quantification or they were not detected at all. Perfluorooctane sulfonate (0.100–2.768 ng.g-1), perfluoroundecanoic acid and perfluorotridecanoic acid were determined in all fish meal samples.
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The issue of determination of tin in environmental matrices
Bušinová, Markéta ; Sommer, Lumír (referee) ; Doležalová Weissmannová, Helena (advisor)
This diploma thesis deals with the retrieval of the content of tin in environmental media, the circulation in them and possibilities of the determination of tin in the environment. Summarizes available information on the properties of tin and its compounds, the occurrence and circulation of tin in environmental and determination of tin in environmental media, attention is paid to the determination of total tin content using method of ET-AAS. The experimental part is focused on optimization methods of determination for the ET AAS and selection of a suitable extraction procedure for determination of total tin content in soils and sediments. The best procedure for the determination of tin in the ET-AAS was applied to samples of soil, sediment and water. As the optimum matrix modifier was chosen the solution of Pd (NO3)2 in 5% ascorbic acid, the optimum pyrolysis temperature was 1400 °C and atomization temperature 2400 ° C. Neither of extraction procedures examined were found to be an appropriate procedure for the determination of tin in environmental samples and further work is necessary to optimize the method of separation.
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Determination of heavy metals in waste energetic materials with using sequential extraction
Kořínková, Alena ; Sommer, Lumír (referee) ; Doležalová Weissmannová, Helena (advisor)
Tato diplomová práce pojednává o stanovení vybraných kovů v energetických odpadech, jako je úletový popílek, škvára, struska, ložový popel, produkt odsíření apod., které pocházejí ze čtyř moravských tepláren. Extrakce kovů z energetických materiálů byla provedena Tessierovou extrakcí. Za tímto účelem byla použita extrakční činidla chlorid hořečnatý (MgCl2), octan sodný (CH3COONa), hydroxylamin hydrochlorid v kyselině octové (NH2OH.HCl v CH3COOH), peroxid vodíku v kyselině dusičné (H2O2 v HNO3) a kyselina fluorovodíková (HF). Extrakce probíhala při teplotách 25°C a 40°C. Ve všech frakcích byly stanoveny olovo, měď a kadmium s využitím atomové absorpční spektrometrie (F AAS, ET AAS) a rtuť metodou AMA 254.
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Utilization of flow-coulometry in study of transport metal ions in humic gels
Kalina, Michal ; Pabst, Willi (referee) ; Klučáková, Martina (advisor)
This diploma thesis deals with the study of non-stationary diffusion of cupric ions in humic gels. The main objective of the work was the optimalization of conditions for using the electrochemical analyzer EcaFlow 150 GLP for the study of diffusion experiments. Next part was focused on reaching of constant concentration profiles of cupric ions in humic gel. Last aim of the study was the bond strength between cupric ions and humic acids. Diffusion was characterized by the values of the diffusion flux and cupric ions concentration profiles in humic gel. The data necessary for calculation were obtained by the electrochemical analyses of the extracts of each slice after diffusion on the EcaFlow 150 GLP. It has been proved that after application of several adjustment is this method suitable for the study of diffusion experiments. By using of different extraction agents was obtained the fractionalization of cupric ions according to the bond strength to humic acids.
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Speciation analysis of selenium in selenized yeast
Motlová, Tereza ; Vitoulová, Eva (referee) ; Diviš, Pavel (advisor)
The aim of the theses was determination of selenium species in yeast Saccharomyces cerevisiae cultivated in medium with added inorganic form of selenium (Sodium Selenite). Concentrations of Sodium Selenite in cultivation medium were 0,1; 1; 10 and 100 mg.l-1. Cultivation was undertaken in fermenting tub for period of 72 hours. Cultivated yeasts were extracted by use of enzymes and subsequently the species of selenium in particular parts of yeasts were determined. In order to determine selenium species, the method of high-performance liquid chromatography in combination with atomic fluorescent spectrometer and technique of hydride generation was used. Having analysed different fractions of the yeasts Saccharomyces cerevisiae it was ascertained that during cultivation the sorption of selenium occurred in form of Se4+ in cell membranes while in cytoplasm no inorganic forms of selenium were found. Furthermore, it was stated that yeasts Saccharomyces cerevisiae are able to metabolically change inorganic forms of selenium to organic forms (selenomethionine), while these forms are present in cytoplasm and they are likely to be bound to proteinic structures of cell membranes. An increase of concentration of Se4+ in cell membranes could be observed as a result of increasing concentration of Sodium Selenite in cultivation medium. In proteinic structures the concentration of organic selenium forms increased only to concentration 10 mg.l-1 of Sodium Selenite in cultivation medium.
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Evaluation of glutathione content in plants as a marker of heavy metals environmental contamination
Borková, Marie ; Stoupalová, Michaela (referee) ; Opatřilová,, Radka (advisor)
Dependence of glutathione concentration on the amount of thallium in the plant was studied. Observed plant was maize (Zea mays) which was divided to two parts – root and overground. Two culture procedures were elaborated where seeds and young seedlings were cultivated in a solution of thallium of concentration 0, 1, 3, 5, 8, a 10 µmol/l. Extraction agents used during extraction were phosphate buffer and solution of ascorbic acid. Determination of glutathione was realized by capillary electrophoresis (CE) and high performance liquid chromatography (HPLC). Diode array detector (DAD) was used in both methods. Quantification of the thallium amount in the plant was done by method of inductively coupled plasma-atomic emission spectrometry (ICP-AES).
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Monitoring of arsenic forms in foodstuffs
Harkabusová, Veronika ; Hrstka, Miroslav (referee) ; Vitoulová, Eva (advisor)
The diploma thesis is dealing with monitoring of arsenic in foodstuffs. The aim of this thesis is the determination of arsenic in samples of fish and rice and the study of forms, in which arsenic occurs, using speciation analysis. Arsenic is known as a toxic element, but its measure of toxicity depends on the chemical form it occurs in. Arsenic is present in the environment naturally or it gets in the environment by human activities. Complete characterization of arsenic compounds is necessary to understand intake, accumulation, transport, detoxification and activation of this element in the natural environment and living systems. The field of arsenic speciation analysis has grown rapidly in recent years, because determination of the total element content is not sufficient in the case of arsenic. Speciation method was done using separation by high performance liquid chromatography and detection by atomic fluorescence spectrometry with hydride generation. Extractable arsenic was present in the form of nontoxic arsenobetaine in all analysed samples of fish. In samples of rice there was confirmed the presence of toxic inorganic species of arsenic, esspecially As (III), but their concentration was at low level.
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Comparison of extraction methods for agriculture soil elemental analysis
Štursa, Václav ; Vespalcová, Milena (referee) ; Diviš, Pavel (advisor)
This bachelor thesis handles with optimization of preparation process of soil samples from vineyards for elemental analysis performed by ICP-MS. First part of the thesis deals with element analysis and its usage in agrotechnics and viticulture, description of toxic and nutrition properties of individual elements and legislation defining appropriate concentration limits of elements in agricultural land. Next part describes commonly used methods for elemental analysis such as AES, AAS, roentgen fluorescence spectrometry and ICP-MS. Finally, sampling methods and methods for sample preparation such as digestion and extraction are described. Experimental part follows up comparison of selected extraction methods (2M HNO3 extraction, temperature assisted 2M HNO3 extraction, aqua regia extraction and microwave-assisted digestion using mixture of HNO3 and H2O2). These methods were applied on certified reference materials. Extracts were analysed by ICP-MS technique Best results were achieved by 2M HNO3 extraction. This extraction method was subsequently applied on real soil samples from vineyard.
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