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Analysis of polyphenolic compounds in selected brewery matrices by HPLC-HRMS method
Zušťáková, Veronika ; Sobotníková, Jana (advisor) ; Mikyška, Alexandr (referee)
The thesis has focused on the separation of proanthocyanidins (Pas) in beer, raw beer material and beer intermediates (wort, hopped wort, green beer) by using high performance liquid chromatography coupled to high resolution mass spectrometric detection. A chromatographic column XSELECT HSS T3 was used for separation of individual proanthocyanidins. Mobile phase was formed by a mixture of 0,1% formic acid in water (A) and 0,1% formic acid in acetonitril (B), separation was conducted in gradient mode. Calibration range for catechin and procyanidin B1 a B2 was linear in the range from 10 µg.l-1 to 200 µg.l-1 and for epicatechin from 5 µg.l-1 to 200 µg.l-1 . Limit of quantitation (LOQ) was set to the lowest point of calibration curve, hence for catechin, procyanidin B1 and B2 was LOQ = 10 µg.l-1 and for epicatechin was LOQ = µg.l-1 . Yield of method of the observed Pas was very good, where yield oscillated around 100%. The method also had excellent repeatability, where the relative standard deviation (RSD) was lower then 20%. After optimization of this method it was used for observation of profile changes during brewery process in catechin, epicatechin, procyanidin B1, B2 and B3. It was discovered, that catechin, epicatechin, procyanidin B1 and B2 originate mainly from hops and procyaniding B3 is...
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Synthesis and Characterization of Arylspiroborates
Sedláčková, Simona ; Jelínek, Ivan (advisor) ; Sobotníková, Jana (referee)
Arylspiroborates have some very interesting properties, which include biological activities and the potential anti-tumor activities. The aim of the thesis was to prepare some complexes using mainly phenolic ligands (catchol, pyrogallol, 3-methoxycatechol, 2,3-dihydroxynaphthalene and 4tertButylcatechol) and their detailed characterization using ESI-QqTOF. With some of these prepared complexes collision experiments were performed and based on the results, the fragmentation mechanisms for these substances were proposed.
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Mobilization of electroosmotic flow markers in capillary electrophoresis
Martínková, Eva ; Křížek, Tomáš (advisor) ; Sobotníková, Jana (referee)
Capillary zone electrophoresis is a separation method used to separate charged substances in electric field. Substances migrate to detector due to their own electrophoretic mobility and electoosmotic flow in capillary. Separation is possible because of electroforetic mobility of substances, which is directly proportional to the charge and undirectly proportional to the hydrated radius of ion. This means that neutral molecules form just one neutral zone, which is detected together. Well absorbing neutral substances are thus used as markers of average (mean) EOF. It was found, that some of the markers have dispositions to be mobilized with respect to the EOF. This mobilization is caused by interactions of free electron pair on atoms of nitrogen or oxygen of marker with components of background buffer. The aim of the study was to measure mobilization of some commonly used markers with different cations of acetate buffer and thus find "ideal" marker, whose mobility is almost the same as EOF and find combinations of marker+buffer, which are better to be avoided. Eleven markers in combination with six cations of background electrolyte were studied. We have found, that relative mobilities of some of chosen markers come up to five percent of limit mobilities of small inorganic cations. An appropriate...
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Optimization of microextraction technique for analysis of water by chromatographic methods
Otrubová, Lucie ; Čabala, Radomír (advisor) ; Sobotníková, Jana (referee)
New liquid phase microextraction (LPME) has been optimized. Plastic adapter with tapered tip was used as extraction device. Concentration of analytes was determined by GC-MS. Face centered design was used to optimize LPME and the results were evaluated by Minitab 16 programme. Volume of sample, volume of extraction solvent, stirring rate, extraction time, ionic strength and time after microextraction were optimized. Response of system was defined as the sum of the peak relative areas. Toluene, tetrachlorethylene, ethylbenzene, xylenes, mesitylene and naphthalene were the studied analytes. Methylhexadecanoate was used as an internal standard. Optimal system conditions were as follows: 20 mL sample volume, 300 μL extraction solvent volume, 20 minutes, stirring speed 700 rpm, no addition of salt, and time after microextraction 3.5 minutes. Determination coefficient was 0.9700 and the lack-of-fit was insignificant which indicated good agreement of the model with the experimental data. The preconcentration factor ranged from 26 (tetrachlorethylene) to 39 (xylenes). The microextraction yield was varied from 39.5% (tetrachlorethylene) to 59.1% (p-xylene and m-xylene). The new method was tested by analyzing real samples of tap water, river water and water from the sewage treatment plant. The samples were...
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Post-column derivatization in HPLC for analysis of amino acids
Vaňkátová, Petra ; Coufal, Pavel (advisor) ; Sobotníková, Jana (referee)
Proteinogenic amino acids are the basic structural building units of proteins. Their analysis is important in many fields, especially in medicine. This thesis deals with one of the methods of derivatization of amino acids in order to increase their absorption in the UV - the post-column derivatization using copper (II) oxide. It is quick, robust and easy-to-use method. Following the nowadays trend in the analysis of free amino acids, this thesis is focused on the HILIC mode separation environment.
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Preparation and testing of capillary packed column sephadex G-10
Tolasz, Jakub ; Coufal, Pavel (advisor) ; Sobotníková, Jana (referee)
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.
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