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Use of LC/MS technique to analysis of some physiologically active natural compounds
Trčková, Marie ; Čáslavský, Josef (referee) ; Kočí, Radka (advisor)
Presented work is focused on application of combined instrumental method RP-HPLC/ESI-MS in analysis of several groups of natural compounds with positive physiological activities. Especially some antioxidants were studied in commonly and abundantly consumed food. Moreover some other substances than standard compounds were observed in complex dies. In conclusion the HPLC/ESI-MS method is comparatively advantageous in phenolic analysis, while another type of ionisation would be used in case of carotenoid compound.
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Importance and impact of phthalates during peritoneal dialysis and current possibilities of their replacement
Nohelová, Gabriela ; Zlámalová Gargošová, Helena (referee) ; Čáslavský, Josef (advisor)
This thesis deals with the importance and influence of phthalates in peritoneal dialysis (PD) and the current possibilities of their replacement. The information about phthalates – esters of phthalic acid - was completed with focus on the most commonly used plasticizer in medical material, bis(2-ethylhexyl) phthalate (DEHP) and its effects on the human organism and the environment. The possibilities of substitution of PVC in peritoneal dialysis were searched and their advantages and disadvantages were evaluated. As the evidence of phthalates absorbed by the human body in carrying out peritoneal dialysis selected studies performed in Germany and in our country, dealing with this issue, were used. High performance liquid chromatography (HPLC) with UV detection at 224 nm or gas chromatography - mass spectrometry (GC / MS) was used here for the determination of phthalates in the blood and dialysate in peritoneal dialysis. Extraction of sample with the suitable solvent and purification of the extract predates the actual analytical determination of sample.
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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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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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