National Repository of Grey Literature 9 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...
Národní inventura persistentních organických polutantů v České republice: Kontaminace potravin, hodnocení duetární expozice, kontaminace populace
Recetox - Tocoen and Associates, Brno ; Černá, Milena ; Ruprich, Jiří ; Drápal, Jiří ; Holoubek, Ivan
Uvedení vývoje monitorování výskytu POPs v České republice od 80. let. Zhodnocení výskytu POPs ve vybraných veterinárních komoditách je následováno popisem systému kontrol cizorodých látek v potravinách v letech 2001 a 2002. Podrobný popis možné dietární expozice s vyhodnocením expozice jednotlivými látkami, uvedením významných expozičních zdrojů, charakteristikou rizika a závěry pro řízení zdravotních rizik je uveden pro polychlorované bifenyly, dioxiny, dibenzofurany a PCBs s dioxionovým efektem, aldrin, endrin, dieldrin, methoxychlor, endosulfan, heptachlor epoxid, hexachlorbenzen (HCB), hexachlorocyklohexany (HCHs), lindan, DDTs a polyaromatické uhlovodíky. Jsou uvedeny výsledky biologického monitoringu, který sleduje zatížení české populace persistentními organickými látkami.

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