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Determination of polycyclic aromatic hydrocarbons in hydrosphere solid matrices by QuWChERS - comparision with present methods
Sudová, Petra ; Nesměrák, Karel (advisor) ; Čabala, Radomír (referee)
Thesis are aimed to the optimization and validation of the QuEChERS method for determination of polycyclic aromatic hydrocarbons in solid matrices of hydrosphere. The QuEChERS method was also used for determination of polycyclic aromatic hydrocarbons in real samples and for comparison of measured results, time and material costs of the method with currently employed methods: (1) accelerated solvent extraction connected with gel permeation chromatography (ASE/GPC), and (2) ultrasonic extraction connected with solid phase extraction (UZ/SPE). According to the validation criteria, the QuEChERS method is suitable for the determination of polycyclic aromatic hydrocarbons in solid matrices of hydrosphere. The QuEChERS technique provides comparable results to ASE/GPC and UZ/SPE. In terms of price and time for sample preparation, the QuEChERS method allows (unlike the methods ASE/GPC and UZ/SPE) fast and inexpensive determination of polycyclic aromatic hydrocarbons in solid samples of hydrosphere.
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Analysis of organic additives in historical mortars
Křížová, Iva ; Čabala, Radomír (advisor) ; Hynek, Radovan (referee)
- 4 - Abstrakt The aim of this diploma thesis was to determine the possibility of identifying the protein and lipid additives, such as blood, gelatine, curd, lard and eggs, in the model samples of lime based mortars using Raman spectroscopy and gas chromatography- mass spectrometry. It was proved that the method of Raman spectroscopy can determine the presence of organic additives in the order of one weight percent. The gas chromatography enables to detect lipid additives from the order of hundredths weight percent. Unambiguous resolution of protein additives can be done in the samples with the concentrations up to the order of one weight percent of the additives.
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Ambient ozon impact on vegetation
Bystrianský, Martin ; Hůnová, Iva (advisor) ; Čabala, Radomír (referee)
Bystrianský: Ambient ozone impact on vegetation - Abstract Ambient ozone is present in the air all around the world. It is natural component of the atmosphere, due to anthropogenic emissions of ozone precursors its concentration rise. That is unlikely, because ozone is toxic. Ozone is formed as a part of photochemical smog from ozone precursors by photochemical reactions. As ozone precursors nitrogen oxides (NOx) and volatile organic compounds (VOC) are called. Their main source is car traffic. Danger of ozone lies in its reactivity. It oxidizes most of organic compounds, especially those containing double bonds. These are present in membrane lipids. Furthermore, ozone forms more reactive compounds than itself - active oxygen species (AOS), free radicals. Ozone effects negatively both human health and vegetation. Ozone disrupts structure of the cells, which for plants means destroy of leaves and needles, photosynthesis disruption and biomass loss. For that, plants have antioxidants system for AOS scavenging. But it has little effect, when concentration of ozone is high during smog period. Therefore, limits for maximal concentration of ozone in the ambient air are set.
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SPE optimization for determination of perfluorinated organic acids
Ševčík, Václav ; Čabala, Radomír (advisor) ; Pacáková, Věra (referee)
This thesis is focused on optimization of preparation of aqueous environmental samples for determination of persistent pollutants - perfluorinated organic acids, which are potentially dangerous for living organisms. The goal of the thesis is optimization of SPE conditions for preconcentration of these compounds for their determination by GC-MS. Perfluorinated organic acids with carbon chain lenghts of C6-C12 were selected as analytes. Effect of sample pH value, effect of type and elution solvent volume, addition of indifferent salt and ion pair reagent have been studied during the optimization. The results show that the extraction efficiency depends on analyte carbon chain length and reaches values from 75 to 110 % for C6 - C8 and 55 to 95 % for C9 - C12 acids. The overall increase in extraction efficiency was more pronounced for acids with shorter chain length (for C6 up to ten times), whereas for long chain acids the improvement was only moderate.
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Toxicity determination of polyfluorinated and perfluorinated organic substances
Otrubová, Lucie ; Čabala, Radomír (advisor) ; Rucki, Marian (referee)
The goal of the bachelor thesis was the determination of toxicity of fluorotelomer alcohols. The toxicity was measured as ET50 by the oligochaete Tubifex tubifex. This test belongs to group of alternative methods which are faster and cheaper but they provide reliable data as well as the presently used classical methods. ET50 is the exposure time when 50 % of Tubifex tubifex individuals stop moving. EC50 of magnese chloride dihydrate was measured for the control of its correctness of determination and its acute toxicity indice is equal to log (EC50) = -0,845 ± 0,033 [log (mmol/l)]. EC50 is the concentration of the tested substance when 50 % of Tubifex tubifex individuals stop moving. 1H,1H,2H,2H-perfluorooctan-1-ol and 1H,1H,2H,2H-perfluorodecan-1-ol were the tested substances. Destilled water and solution of dimethyl sulfoxide in water (5 %) were used to prepare the saturated solutions of the tested substances. The conncentrations of the saturated solutions were determined on GC-MS by absolute calibration method. The value of log (EC50) for dimethyl sulfoxide solution was measured to determine how it influences Tubifex tubifex during exposure time of 2,5 hours. KEY WORDS: fluorotelomer alcohols, alternative method, Tubifex tubifex
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Development of capillary electrophoretic method for determination of phosphorylated components of bacterial cell membranes
Červinková, Jana ; Čabala, Radomír (advisor) ; Coufal, Pavel (referee)
Title: Development of capillary electrophoretic method for determination of phosphorylated components of bacterial cell membranes Author: Jana Červinková Department: Department of analytical chemistry Supervisor: RNDr. Radomír Čabala, Dr. Abstract: The bachelor work reviews the present state of knowledge of the analyses and determination of phosphorylated compounds present in the bacterial cell membranes. This group of compounds is represented mainly by phosphatidylglycerol, cardiolipine, and phosphatidylethanolamine and minority phosphatidylserine, phosphatidic acid and lysylphospatidylglycerol. Together with fatty acids these substances are the main components of cell membranes and they could be, to a certain degree, applied to either identification of bacteria or the study of bacterial behaviour at different conditions. Partially or fully non-aqueous capillary electrophoresis analytical method with spectrophotometric detection would be developed for their determination. Optimum experimental conditions for the separation of standards of selected compounds should be found within the framework of the bachelor thesis. Keywords: phosphorylated compounds, bacterial cytoplasmic membrane, capillary electrophoresis, thin layer chromatography, Bacillus subtilis.
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Determination of distribution coefficients of perfuorinted compounds in 1-octanole/water system
Skrottová, Anežka ; Čabala, Radomír (advisor) ; Nesměrák, Karel (referee)
The aim of the bachelor thesis was to determinate distribution coefficients of 1H,1H,2H,2H-Perfluoro-1-octanol and 1H,1H,2H,2H-Perfluoro-1-decanol in 1-octanol/water system. Method used for measurement was the shake flask method. Measured substance is distributed between two immiscible liquids after intensive shaking. Concentration in both phases was measured after equilibration with Gas Chromatography - Mass Spectrometry. Knowledge of distribution coefficients helps to estimate toxic potential of substance. Logarithm of distribution coefficient of measured substances was about 3,5. It means, that measured substances are lipophilic. It is associated with their high bioaccumulation potential. They accumulate in organism and their excretion is very difficult. They also accumulate in abiotic environment. So they have negative effects on it and their production is reduced.
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Preconcentration and determination of organic perfluorinated acids by gas chromatography
Maradová, Doubravka ; Čabala, Radomír (advisor) ; Feltl, Ladislav (referee)
A rapid and simple derivatization procedure has been developed for gas chromatographic determination for of perfluorinated acids (C6-C12), using isobutyl chloroformate to convert the acids into more volatile isobutylesters, under catalysis by pyridine. The procedure was optimized in an acetonitrile medium and applied to GC techniques with electron-capture detection (GC-ECD) and mass spectrometry with electron-impact ionization (GC-EI-MS), for the sake of comparison, HPLC with electrospray-ionization MS (HPLC-ESI-MS) was also tested. The LOD and LOQ values obtained for these three techniques were compared, and the lowest LODs were obtained with GC-ECD (0,1-1,8 µg/ml). By comparing the sensitivity of analytical separation method utilizing the same derivatization technique for the analysis of PFA, GC-ECD proves to be more appropriate and sensitive than GC-MS. In addition, an evaluation of the various derivatization techniques for GC-ECD, GC-MS and HPLC-MS method without derivatization, shows that GC-ECD method is superior to GC-MS or HPLC- MS.
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