National Repository of Grey Literature 10 records found  Search took 0.01 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...
Contactless conductometry for shallow parts of geological medium
Podolník, Jan ; Dohnal, Jiří (advisor) ; Kněz, Jaroslav (referee)
The task is focused on the issue of contactless conductometry for shallow parts of geological medium and it consists of two connected parts, search and experimental. The first part includes fundamental theoretical principles of contactless conductivity measurement, summary of presently manufactured electromagnetic devices (ground conductivity meters) and finally it presents the potentialities of using conductometry for detection and monitoring of contaminants. The basis of the second part comprises the field test measurements with the instrument CMD (producer GF Instruments, s.r.o. Brno) on the selected locality, namely for several depth levels. The contents of this part include the field measurement, data processing and complex interpretation of the results in connection with geological conditions of the locality, petrophysical knowledge and with the stability of the device.
Contaminant binding to colloids in water from a mining/smelting area
Walter, Dominik ; Ettler, Vojtěch (advisor) ; Faimon, Jiří (referee)
This study deals with the association of trace elements with colloids and particles in surface waters and groundwaters of mining and smelting district of Příbram. Colloids were studied using combination of cascade filtration a tangential flow ultrafiltration method to separate individual colloid fractions. Colloids were separated by filtration membranes with nominal pore size 0,8 μm, 0,45 μm, 0,1 μm, 100 kDa, and 5 kDa. Water samples were analyzed using ICP-OES, ICP-MS and HPLC. The data were used for thermodynamic modeling using PHREEQC-2 programme. The results show that major and trace elements can be divided into several groups, based on their abundance in individual size fractions. Most elements dominate in fraction of truly dissolved matter as dissociated ions (< 5 kDa), maximum concentration in colloid fraction is 5-20 % and almost exclusively in fraction 5 kDa - 100 kDa. Gradual decrease of concentration in all fractions at low ionic strength (1,2 mmol/l) was observed in case of elements such as As, Co, Cr, Si, Sb and U. Gradual decrease of concentration in several samples was observed for Cd, Fe, Pb, Mn and Zn. Dominant binding to colloids and particles in surface waters was observed for Fe and Pb, where these fractions accounted for over 90 %. The main factor influencing colloid...
Analýza možností sanace vybrané staré ekologické zátěže
Balušková, Zuzana
This Master's thesis is devoted to the issue of old ecological burdens. Literal review summarizes general information about old ecological burdens, selection process of remediation, remeditaion technologies, in both saturated and unsaturated zones, further divided into biological, physical and chemical methods. Within the content cross-cutting legislation regarding to old ecological burdens is summarized. Second part of this thesis is dedicated to specific old ecological burden namely Laguny Ostramo in Ostrava. Selected burden was evaluated by the risk analysis and proposals for the completion of remediation were suggested.
Solidification product made of hazardous waste and possibilities of its launch to the market
Hodul, Jakub ; Snop, Roman (referee) ; Drochytka, Rostislav (advisor)
Diploma thesis deals with the possibility of using solidification technology to transform the hazardous waste with the aim to achieve the material utilization of solidification products. The aim of the thesis is to determine a suitable solidification formula for solidification product made of hazardous waste that will ensure properties of the solidification product, those will allow its placing on the market.
Ecotoxicological evaluation of sediments
Dobešová, Zuzana ; Doležalová Weissmannová, Helena (referee) ; Zlámalová Gargošová, Helena (advisor)
Sediments of lotic and lentic water can be a reservoir of a number of contaminants, which can enter the aquatic ecosystem either due to the controlled discharge of waste water or leakage of various accidents or technological devices. Sediments can hereby affect not only the aquatic ecosystem, but also the terrestrial system in the case that they will be used as fertilizer or as a material for the recultivation. For this reason it is important to consider their potential ecotoxicity. Sediments were subjected to ecotoxicological bioassays and their potential ecotoxicity was assessed. The phytotoxicity assays on terrestrial plants Sinapis alba, Lactuca sativa and Allium cepa were used and the effects of aqueous extracts of sediments on the inhibition of growth their root were evaluated and the value of IC50 was determined. For the ecotoxicological assessment of sediments and determination of IC50 value also Lemna minor as a representative of aquatic plants was selected. For more objective assessment of the sediment ecotoxicity aquatic invertebrates as Artemia salina and Daphnia magna were selected and the value of LC50 or EC50 was determined.
Residues of inhibitors in cow´s milk
STŘELEČKOVÁ, Veronika
Milk, in our territory frequently used cow?s milk, is very important nutrient. Its importance consists in the contents of valuable proteins, easily digestible milk fat, lactose, vitamins and minerals. The quality of raw cow?s milk is characterised by many indicators, for example total number of microorganisms, number of somatic cells, content of basic constituents (fat, protein, lactose, non-fat solids), freezing point or occurrence of undesirable foreign and inhibitory substances. Residuals of inhibitory substances (RIL) are one of the main criteria of raw milk hygienic quality, where they can appear for example due to prevention and treatment of mastitis. The risk of occurrence and spread of bacterial resistance, disruption of intestinal microflora, allergic reactions and RIL toxic effects, both in human and veterinary medicine, belong among the biggest risks of RIL presence in food and raw materials of animal origin, including milk. Inhibitory substances have an inhibiting effect on development and activity of microorganisms and in particular in milk industry they affect the activity of dairy cultures causing significant production problems. Their presence in milk causes problems when producing cheese, during fermentation of yoghurts and other fermentation during milk processing. Prevention of RIL occurrence depends especially on adherence to basic breeding and veterinary measures when using drugs and medicines, on technology discipline in primary production and regular and strict control of RIL contents in milk from the primary production up to processing when various screening detection methods are used. It is very important to deal with the matter of RIL in milk in connection with quality standards, national legislation and European Union legislation and to control methods used for their detection and verification.
The main extraneous substances ingestion by nutriment
BUCHAROVÁ, Eva
This work treats of main extraneous substances ingestion by nutriment. It means additives and contaminants. Present of this substance in food is regulated by legislation. In Czech Republic, there are, laws of food in accordance with laws of EU. In Czech Republic, there are, additives and contaminants controlled by SZPI and SVS. European control institution is EFSA and throughout the world works FAO/WHO. Chief aim of this work is to find out differences in foreknowledge of the main substances ingestion by nutriment between men and women.

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