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Possibilities of identification of flavonoids in environmental matrixes
Magdechová, Andrea ; Zlámalová Gargošová, Helena (referee) ; Vávrová, Milada (advisor)
Inherent part of plants are active substances; flavonoids belong to this group. They are used in medicine, cosmetics and they shloud be a part of our diet because of their positive effects. This bachelor thesis is focused on the identification of flavonoids in selected types of coniferous trees and moss. Pines, firs and spruces were selected as the representants of coniferous trees, together with mosses Polytrichum formosum and Rhytidiadelphus subpinnatus. Flavonoids were isolated using liquid-liquid extraction and identified using thin layer chromatography and high-performance liquid chromatography.
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High pressure modification of the simple automated liquid chromatographic system for splitless nano column gradient separations
Šesták, Jozef ; Kahle, Vladislav
Our simple liquid chromatographic system for splitless gradient nanocolumn separations at backpressure up to 50 bars was modified to run analysis under the pressure up to 300 bars. Programmable syringe pump was equipped with a 250-L high-pressure syringe and mobile phase gradients were created and stored in relatively long capillary. Available linear gradients of volumes from 5 to 50 L traced by uracil are presented. Sample introduction was performed as separate step and real large volume of sample (tens of microliters) could be injected and preconcentrated on-column. Relative standard deviation of retention times and peak areas were received (RSD < 0.3 % and RSD < 5 % respectively).
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IEF and HPLC-based methods for efficient bacterial characterization
Kubesová, Anna ; Šalplachta, Jiří ; Moravcová, Dana ; Horká, Marie
Pectobacterium and Dickeya species are responsible for blackleg and tuber soft rot diseases on crop and ornamental plants. Recently, a more virulent and aggressive Dickeya type of E. chrysanthemi was described and it becomes serious problem for potato production in Europe. In this study, we suggest procedures using two commonly available laboratory techniques, gel isoelectric focusing and liquid chromatography, for differentiation and characterization of Pectobacterium and Dickeya species. We have confirmed that fingerprinting approach can be used for bacterial differentiation, which can be further used in rapid diagnosis of plant disease.
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Occurrence of perfluorinated compounds in fish from rivers of the Czech Republic
HOLAŇ, Viktor
The object of this thesis is the assessment of fish contamination by selected foreign substances as perfluorinated compounds. these sites were selected for the thesis' purpose: Bečva - Dluhonice, Elbe - Přelouč, Bílina - Usti nad Labem, Jizera - Předměřice, Sázava - Nespeky and Otava - Topělec. Fish were caught by electrofishig. The concetrations of contaminants were measured in fish muscle and liver. The analysis were performed using liquid chromatography (HPLC - MS / MS). Concentrations of PFOS, PFNA, PFOA, PFHxS and PFHpS in fish muscle and liver tissues were monitored.
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ELECTROCHEMICAL DETECTOR WITH ELECTRODES ARRAY AND ROTATING DISK
SAJDLOVÁ, Zuzana
The thesis deals with the testing and optimization of hydrodynamic conditions of the electrochemical detector, which consists of a flow cell containing the electrochemical sensor with an array of electrodes. The flow cell includes a rotating disc-shaped component, which allows radial flow of analytes along the sensor electrodes. This principle imitates the rotating disk electrode, with the difference that here the electrodes are immobile. Hydrodynamic phenomena in this case are similar to RDE. Therefore, the theoretical part of my work deals with hydrodynamics and mass transfer for the well-described case of rotating disk electrode. It was found that in the current set-up under certain conditions, an analyte flowed back from the output cell channel to the sensor, even at the laminar flow. This causes a nonlinear response of the electrodes and their low reproducibility. The solution is to reduce the distance between the rotation component and the electrodes surface and reduce flow speed of analyzed liquid towards the sensor. A novel type of sensor with annular electrodes was designed and tested. It showed four times higher conversion rate of the analyte compared with the originally used AC9 electrochemical sensor having electrodes in the form of full circles lying on a circumference of a common circle. Based on calculations, conversion of the analyte on the plane electrode can be increased up to 100% when using this annular sensor, adjusting flow cell and reducing of the input flow rate. The detector was connected to the liquid chromatograph and its function was tested on two substances - ascorbic acid and dopamine. For the current detector these parameters were set: dynamic range, linearity, noise, detection limit, time constant and the temperature range at which the detector can be operated.
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LC-MS analysis based on probabilistic approach
URBAN, Jan
Liquid chromatography (LC) in tandem with mass spectrometry (MS) is a measurement tool for obtain information about the compounds in the investigated extracts. There were already developed methods for processing and analysis of measured data sets. However, only partial problems of processing/analysis task were handled independently. Therefore, the rst part describes existing methods and techniques commonly used in the LC-MS for the processing and analysis today. In this thesis an approach based on the theory of systems is used for description of abstract model above the measured data. This model encapsulated all processing/analysis steps into appropriate and consistent mathematical space. The creation of this model via description of the measurement device and data outputs is introduced. Abstract model of LC-MS data set is used to decompose the measurement into three partial contributions, the analyte signal, the random noise and the systemic noise. The separation process of the signal could be estimated using the probabilistic approach. That probabilistic approach to the LC-MS analysis was implemented in the developed software, which was published in the Bioinformatics Journal.
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Měření vnitřní difuze pomocí kapalinové chromatografie
Soukup, Karel ; Schneider, Petr ; Šolcová, Olga
Liquid chromatography setup was used in liquid diffusion studies. The Kubin-Kucera model was employed for mathematical description of processes inside the chromatographic column. Effective diffusivities were evaluated by time-domain fitting chromatographic response peaks of columns packed with tested porous particles. Axial dispersion coefficients were determined independently by analysis of response peaks of columns packed with nonporous pellets; this improved significantly the confidence of effective diffusion coefficients. An attempt was made to exclude the end effects of chromatographic columns by analyzing response peaks of pairs of columns differing by lengths.
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