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Study of the Selected Types of Sulphur Compounds in Beer and Brewing Materials
Mikulíková, Renata ; Ventura, Karel (referee) ; Ventura, Karel (referee) ; Čáslavský, Josef (referee) ; Márová, Ivana (advisor)
Much attention has been recently devoted to sensorially active substances affecting beer quality in the Czech Republic and worldwide. Among them, the heterocyclic and sulphur containing compounds play an important role, some of them with high sensorial activity even in extremely low concentrations. Trace amounts of these compounds, which can be frequently found in foods, participate in formation of their aroma and this effect can be generally evaluated as favorable However, in malt or beer it is true only to a limited extent and the presence of heterocyclic and sulphur containing compounds are in this respect assessed rather unfavorably. The aim of the present study was to provide a survey about of problems in the field of sulphur containing compounds in barley, malt and beer, to describe metabolic paths leading to their formation and to verify experimentally possibilities of their determination using modern analytical methods. Sulphur-containing amino acids are a natural part of barley, malt and beer and are precursors of the origin of volatile sulphur substances. The most frequently occurring sulphur amino acids, metionine, cysteine and homocysteine, were selected for analytical monitoring. The method of gas chromatography was used to determine sulphur-containing amino acids in barley, malt and beer. Prior to the analysis, sulphur-containing amino acids were derived and volatile N(O,S)-ethoxycarbonyl propyl esters were formed; they were subsequently analyzed using the gas chromatography with mass detector (GC/ MSD) and the gas chromatography with flame photo detector (GC/ FPD). Direct analysis of sulphur volatile substances is possible only rarely as they are found in the analyzed matrices (malt, beer) only in very low concentrations ( g/kg,l - ng/kg,l). Before the analysis, the analytes must be extracted from the matrix and concentrated. The modern analytical methods SPME (Solid Phase Micro Extraction), SPDE (Solid Phase Dynamic Extraction) and TDAS (Thermal Desorption Autosampler) were experimentally compared for the extraction and subsequent concentration of sulphur volatile substances. The method of gas chromatography with flame photo detector was used to determine sulphur volatile substances. Following volatile sulphur substances were monitored: dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide, carbon disulphide, ethyl sulphide, diethyl disulphide, methionol, 3-methylthiophen, ethyl thioacetate, 2-methyl-1-buthanthiol. Only metionine was detected in significant amounts in the barley samples analyzed. Not only content but also dependence on a variety and locality were studied. Further, changes in methionine, cysteine and PDMS content during malting were followed. Results proved a significant decline in these substances content depending on the kilning temperature. Three types of fibers were tested for the analyses of the selected volatile sulphur substances in beer in the SPME method. PEG - a fiber with stationary phase Carbowax, PDMS - a fiber with stationary phase polydimethylsiloxan and a combined fiber CAR/PDMS - Carboxen and polydimethylsiloxan. Carbon disulphide, methionol, dimethyl sulphide, 3-methylthiophen and diethyl disulphide were detected with this method. Content of the other analyzed volatile sulphur substances was below the limit of detection. Further was tested usage the SPDE and TDAS methods. Both methods appear to be the suitable for the determination of volatile sulphur substances in beer.
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Evaluation of Polymer Separation System Purifier N 1024 device efficiency
Duliková, Michaela ; Charvátová,, Michaela (referee) ; Čáslavský, Josef (advisor)
In this Diploma Thesis the recycling of the PET bottles in the company PETKA CZ, a.s. is under focus. Thesis describes the Italian technology AMUT designed for physical recycling of the PET bottles. The primary goal is the quality of the final recycled product, PET flakes, particularly in the context of undesirable admixtures such as PVC, other polymers and impurities. Due to the deteriorating quality of the PET flakes the equipment Polymer Separation System Purifier N 1024 has been tested, which had significantly reduced admixtures in PET flakes. As it turned out, the current procedures for solving problems with the PET flakes quality are no longer sufficient.
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Application of GDA-2 instrument in practical activities of Fire Rescue Units
Rousková, Renata ; Mika, Otakar Jiří (referee) ; Čáslavský, Josef (advisor)
This diploma thesis is aimed at the use of mobile analyzer Gas Detector Array GDA 2 by Fire Brigade Units of the Czech Republic. The goal of the theoretical part was to get acquainted with this instrument and with the possibilities of its use, to describe the principle of analytical methods used in this analyzer. The experimental part was aimed on the analyses of toxic gases and vapors in the air and on the comparison of obtained result. Final part of diploma thesis evaluates the contribution of mobile analyzer GDA 2 for rapid identification of unknown toxic compounds by Fire Brigade Units of the Czech Republic.
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Methods for determination of tumor markers in the blood plasma and their clinical significance in diagnosing
Toman, Karel ; Márová, Ivana (referee) ; Čáslavský, Josef (advisor)
The thesis discusses the methods of determination of tumor markers and their clinical importance in medical diagnostics. The theoretical part describes clinically important tumor markers and also the chemiluminescent immunoassay methods used for their determination. The practical part of the thesis describes the introduction of new chemiluminescent methods for the determination of tumor markers in routine operation, evaluates its basic analytical parameters and compares it with the existing immunoturbidimetric method. The practical part also presents results of monitoring of cancer patients with various tumors, which is performed by evaluation of the values of tumor markers. Comparison of our method with other methods within the context of System of external quality control is also documented.
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Distribution of pharmaceuticals in wastewater treatment plants
Šilhánková, Lenka ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
This bachelor’s thesis deals with a trending topic – wastewater distribution of pharmaceuticals proven to be toxic to non-target organisms – specifically, the occurrence of beta-blockers, plentifully used in treating hypertension and other cardiovascular diseases, is discussed. Members of this group, Atenolol, Acebutolol and Bisoprolol were chosen for closer study. The elimination of these chemicals was observed in three wastewater treatment plants (WWTP) with different treatment technologies and various number of population equivalents. For said analytes, UHPLC with UV/VIS detection using diode array detector (DAD) method was optimalised. A part of this thesis also deals with optimalization of isolation and concentrating the analytes. Unfortunately, the described method was not suitable for real sample analysis, because in most samples, the limit of quantification or even the limit of detection was not exceeded. It would be best for an analytical method with higher sensitivity, e. g. mass detector, to be used. The data gained in this experiment do not hold any informational value about the effectiveness of WWTP, as the exact amount of Acebutolol in effluent was measured only in one case. Based on the to-date executed analysis, it is impossible to conclude whether the quality of the treated water, concerning the content of aforementioned pharmaceuticals, is in any way ideal.
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Flame retardants and their penetration into the terrestrial ecosystem
Chytil, Václav ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
This diploma thesis was focused on the analysis of four compounds from brominated flame retardants group, namely pentabromoethylbenzene, hexabromocyclododecane, hexabromobenzene and tetrabromobisphenol A. Matrices were represented by four soil samples and four seat of fire samples. In addition, bisphenol A was also determined. First of all, process of extraction of analytes from matrices was optimized. Three different extraction techniques were tested (pressurized solvent extraction, microwave-assisted extraction and ultrasound-assisted extraction). Next step was to verify stability of target compounds in strongly acidic conditions and to optimize clean-up of extract by column chromatography. Gas chromatography with electron capture detection (GC-ECD) was chosen as an appropriate analytical method for the determination of brominated flame retardants. Bisphenol A was determined by gas chromatography with mass spectrometric detection (GC-MS). The derivatization of phenolic analytes before their final analytical determination was also essential.
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Determination of linear synthetic aromatic compounds in abiotic and biotic matrices
Tulková, Tereza ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
Synthetic musk compounds are artificial organic compounds with a smell similar to the odor of a natural musk. The most recently discovered and also the least known group of artificial musks is linear musk compounds. These substances are now often used in cosmetics, personal care products, detergents and various cleaning products. They have leaked into all the major environment components, especially into the hydrosphere. There has been great attention drawn to synthetic musk compounds in the last few years because of their environmental impact. The aim of this thesis is to identify twelve linear musk compounds (linalool, 2-cyclohexylethanol, fresco menthe, citronellol, HSA, isobornyl acetate, arocet, aroflorone, allyl cyclohexyl propionate, lilial, isoamyl salicylate and hexylcinnamic aldehyde) in waste water samples. The samples were taken at three different waste water treatment plants (WWTP) in South Moravian region (WWTP Brno-Modřice, WWTP Luhačovice and WWTP Hodonín). Each of these treatment plants has a different equivalent number of inhabitants. At first, a working method was optimized, then applied on real waste water samples. Solid-phase microextraction (SPME) technique was used for the extraction of analytes. Gas chromatography–mass spectrometry (GC/MS) was then used for identification and quantificaton of the studied compounds.
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Characterization of the chemical composition of the tar produced in the gasification of biomass
Mahelová, Zora ; Vávrová, Milada (referee) ; Čáslavský, Josef (advisor)
Biomass is a renewable source of energy and represents an acceptable alternative to fosil fuels. Usable methods of energetic use of biomass are combustion and gasification. Main interest is focused on gasification in last years. Gasification is based on conversion of organic material to usable gaseous product called syngas, which can be used as a fuel for energy production. Large amount of tar is formed as a by-product of incineration and gasification of biomass. Tar is composed by various mixture of organic substances, has a negative effect on operating conditions and is a potential threat to environment. Experimental part of this study was focused on analysis of tar obtained by gasification of various kind of biomass. Selected groups of hydrocarbons and oxygen compounds were identified in analysed samples. Individual biomass samples were compared regarding to determined relative content of selected substances. Analysis was done by complete twodimensional gas chromatography with mass spectrometric detection (GCxGC/TOF-MS).
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