National Repository of Grey Literature 15 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Analysis of sensory and toxicologically important compounds in beer
Vrzal, Tomáš
One of the most relevant group of toxicologically significant compounds in beer are N-nitrosamines. In this thesis, the attention was paid especially on non-volatile nitroso compounds whose concentrations in beer, a chemical structure, and a biological effect has not been known yet. For the reason of the lack of knowledge regarding this compound group, the method for their sensitive detection by chemiluminescence detection after gas chromatographic separation was developed. This method permits a classification of detected nitroso compounds to different groups (N-nitroso, C-nitroso, and combination of C-nitroso and nitro) and distinguish them from interferences. The method is based on recording of a pyrolytic profile of each chromatographic peak, the profiles are then processed by discriminant analysis. The method has been developed for finding and structural identification purposes of these unknown compounds. Its application on an artificially nitrosated beer sample, together with gas chromatographic tandem mass spectrometric analysis, led to structural identification of several representatives of nitroso compounds. Sensory active compounds in this thesis are represented by carbonyl compounds and fatty acids. Carbonyl compounds - furfural and hydroxymethylfurfural - were used during the development...
Analysis of sensory and toxicologically important compounds in beer
Vrzal, Tomáš ; Čabala, Radomír (advisor) ; ADAM, Martin (referee) ; Feltl, Ladislav (referee)
One of the most relevant group of toxicologically significant compounds in beer are N-nitrosamines. In this thesis, the attention was paid especially on non-volatile nitroso compounds whose concentrations in beer, a chemical structure, and a biological effect has not been known yet. For the reason of the lack of knowledge regarding this compound group, the method for their sensitive detection by chemiluminescence detection after gas chromatographic separation was developed. This method permits a classification of detected nitroso compounds to different groups (N-nitroso, C-nitroso, and combination of C-nitroso and nitro) and distinguish them from interferences. The method is based on recording of a pyrolytic profile of each chromatographic peak, the profiles are then processed by discriminant analysis. The method has been developed for finding and structural identification purposes of these unknown compounds. Its application on an artificially nitrosated beer sample, together with gas chromatographic tandem mass spectrometric analysis, led to structural identification of several representatives of nitroso compounds. Sensory active compounds in this thesis are represented by carbonyl compounds and fatty acids. Carbonyl compounds - furfural and hydroxymethylfurfural - were used during the development...
Analytical chemistry unravels the diversity and function of chemicals used for communication and defence in termite societies
Krasulová, Jana ; Bosáková, Zuzana (advisor) ; Pacáková, Věra (referee) ; Lapčík, Oldřich (referee)
Analytical chemistry plays a crucial role in studies on chemical ecology and only the development of sophisticated methods enables the detection of biologically active compounds that are usually present in minute quantities and often in very complex mixtures. My thesis is dedicated to the application of modern analytical techniques and instrumentation to unravel the identity, chemical diversity and function of semiochemicals and defensive compounds used by various species of termites. The first section of this thesis aims at the identity of chemicals used in communication, the pheromones. I studied the chemistry of the trail-following communication in three selected species of termites. Besides the identification of (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol, the most frequent termite trail-following pheromone, as the trail-following pheromone in Psammotermes hybostoma (Rhinotermitidae), I participated in the description of two new structures, (10Z,13Z)-nonadeca-10,13-dien-2-one in Glossotermes oculatus (Serritermitidae) and syn-4,6-dimethylundecan-1-ol in Hodotermopsis sjoestedti (Archotermopsidae). We identified (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol to be the female sex pheromone in Psammotermes hybostoma, and syn-4,6-dimethylundecanal to be the male sex pheromone in Hodotermopsis sjoestedti. I also...
Analytical Chemistry in secondary grammar school
Součková, Danuše ; Jelínek, Ivan (advisor) ; Richtr, Václav (referee) ; Schwarzová, Karolina (referee)
Mgr. Danuše Součková: Analytical chemistry in secondary grammar school. Summary of Ph.D.Thesis Charles University in Prague, Faculty of Science, Department of Teaching and Didactics of Chemistry At the end of my thesis about the importace of chemical experiments in chemical education and especially about the importace of analytic chemistry in secondary grammar schools I'd like to summarize the most important ideas from particular chapters. I think that the objects I have determined at the beginnig, have been filled and my work will help to perceive analytic chemistry as an integral part of chemistry education in secondary grammar schools. I have emphasized importace of chemical experiment and its use in analytical chemistry education. I have pointed a possibility of working relation among school subjects and a possibility of putting several cross-sectional topics into analytic chemistry education. Other object was to check students' knowledge. I have also intent on particular experiments and I have dividend them into several groups and I have prepared them to be put just into lessons by teachers and some notices and solutions are added. I have described the work during the experimental lessons, the equipment for them, specific matter of analytical chemistry. When we understand the function and...
Preparation and testing of capillary packed column sephadex G-10
Tolasz, Jakub ; Sobotníková, Jana (referee) ; Coufal, Pavel (advisor)
Sephadex is a common sorbent in biochemistry for separation of molecules of a wide range of molecular masses. Sephadex is also used for purification or desalination of isolated proteins. Up to now, the gel chromatography has been performed in wide separation columns. Therefore, the isolation techniques for proteins had to be very effective to isolate enough proteins as a sufficient amount of the sample. The preparation and application of a capillary separation column packed with sephadex could decrease the needed sample amount and enable work with hardly isolable proteins obtained only in small quantities. In this bachelor project, the capillary column was packed with sephadex using the slurry packing procedure. The principle of monolithic columns was used to create a gel in the column. The column was packed in organic solvent firs, and then hydrated when flushing with water to generate the gel.
Polarographic analysis of water
Klečka, Tomáš ; Rozman, Jiří (referee) ; Čížek, Martin (advisor)
This bachelor's project creates the necessary theoretical foundation of polarography and voltametry in the first part, which is needed to successful measurement using these technics. In the second part there is realized measurement with anodic stripping voltametry and accomplished evaluation in MATLAB. Finally there is example of procedure for laboratory task with polarograph.
Electrochemical Multichannel Device for Toxicologic Purposes
Navrátil, T. ; Josypčuk, Bohdan
Nobody doubts that electrochemical methods can be very useful in toxicologic analysis. However, in some cases it is necessary to carry out such analysis applying in relatively short time and applying minimal human labor.
Výsledky z Mezinárodního semináře analytické chemie a toxikologie 2006

It is a book of proceedings from international seminar "Analytical Chemistry and Toxicology".
Voltammetric determination of genotoxic compounds using solid amalgam electrodes
Barek, J. ; Čížek, K. ; Fischer, J. ; Navrátil, Tomáš ; Josypčuk, Bohdan
Possibilities of voltammetric determinations of genotoxic organic compounds for environmental purposes were studied. Traditional mercury electrode was replaced by solid amalgam electrodes. It is possible to conclude that the obtained results are comparable with those, obtained on other types of electrodes.

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