National Repository of Grey Literature 76 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Analysis of pesticides in the environment using the QuEChERS method
Vašinková, Alena ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
This thesis focuses on pesticides in the environment, more specifically in cereals. Pesticides were monitored in various samples of cereals (barley, rye, oats, and wheat) within the thesis. The monitored substances were isolated in selected samples and concentrated using the QUECHERS method. Gas and liquid chromatography were used to determine pesticides. The theoretical part consists of the common types of pesticides, divided by the ease with which these substances into food and their impact on humans and environment. It also mentions current health protection legislation and environmental legislation.
Characterization of organic substances in biochar and their release in the soil ecosystem
Bočán, David ; Doležalová Weissmannová, Helena (referee) ; Mravcová, Ludmila (advisor)
The aim of this master’s thesis was to optimize the extraction of 38 PAH and 7 PCB compounds from samples of commercially available biochar and then apply the most suitable extraction method to real samples of biochar and soil. The concentrations of mentioned compounds were determined by using gas chromatography with mass spectrometry detection. Finally, from these concentrations in individual samples, a rate of release of these compounds from biochar to soil was determined. The theoretical part was focused on summarizing the process of biochar production and its properties. The next part deals with compounds that can be present in biochar, their physicochemical properties and effects on organisms and the environment. Also, a most common ways of extracting and determinating these compounds are mentioned. The final part focuses on soil and its characteristics and the changes it undergoes when biochar is applied to it. In the practical part an extensive optimization of extractions using a PSE extractor and thermal desorption extraction was conducted. After determining optimal conditions for both types of extraction methods, these methods were applied to real samples of biochar and soil. Qualitative analysis was carried out using GCxGC-TOF mass spectrometer and quantitative analysis by MRM method on GC-MS2 mass spectrometer.
Use of the QuEChERS method for the analysis of fluoroquinolone antibiotics in soil
Brabcová, Kristýna ; Zlámalová Gargošová, Helena (referee) ; Mravcová, Ludmila (advisor)
The content of this master's thesis is an application of frequently used extraction method QuEChERS on soil or other samples like litter or manure containing fluoroquinolone antibiotics. In the theoretical part of this thesis are chapters describing drugs, antibiotics and antibiotic resistance. Fluoroquinolones are described in more details with their properties, appearance and behaviour in the environment. The last chapter is focused on analytical methods. In the experimental part of this thesis is chosen in accordance with available publications the most suitable extraction method. This method is tested and optimized on soil samples. The optimized method is applied on the real soil and poultry litter samples to determine the amount of ciprofloxacine and enrofloxacine. This extraction method is used on other fluoroquinolone antibiotics (norfloxacine, ofloxacine, pefloxacine, moxifloxacine) in soil. All of the samples were analyzed by LC-MS.
Analysis of fluoroquinolone antibiotics in the soil
Vdolečková, Monika ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
The thesis dealt with the global problem of the occurrence of pharmaceuticals in the environment, specifically fluoroquinol antibiotics (ciprofloxacin and enrofloxacin), which are among other critically important antibiotics. These drugs enter the soil environment through the application of already contaminated animal waste (e.g. manure) or through wastewater used in irrigation or through the application of treated sewage sludge, which may contain drug residues. Increasing concentrations of these antimicrobial drugs in the environment provide an environment for the emergence and spread of microbial resistance. The accumulation of these drugs then leads to the emergence of resistance to these antibiotics. The experimental part of the thesis focused on the optimization of a method for the extraction and subsequent determination of fluoroquinolones in soil and litter. For this purpose, parameters related to the extraction yield of fluoroquinolones from the soil matrix were optimized, such as sample weighting, selection of a suitable extraction medium, SPE performance, elution method from the SPE, etc. Extraction recoveries of 70 to 140 % were achieved as part of the optimization. Finally, the optimised method for extraction of fluoroquinolones from poultry litter and soil samples provided by the ÚKZÚZ was used. The experimental results confirm the long-term persistence of these drugs in the environment.
Solubilization of water-insoluble vitamins into vesicular systems based on ionic amphiphilic pairs
Kolomá, Nikola ; Mravcová, Ludmila (referee) ; Mravec, Filip (advisor)
This thesis deals with the characterization and preparation of catanionic vesicular systems and their interaction with water-insoluble vitamins. Catanionic vesicles systems was prepared from two differently charged sufractants CTAB and SDS in formation ion pair amphiphile. Stability of vesicles was secured by adding cholesterol with positively charged surfactant DODAC. Were selected vitamin A and vitamin E for solubilization into these vesicles. The next part of this work was focused on determining the efficiency of incorporation these vitamins into the HTMA-DS vesicular system. The characterization of these systems was improved by measurement on a UV-VIS spectrometer, DLS and by HPLC with UV-VIS detector. During measurement by UV-VIS and HPLC the efficiency of solubilization of vitamin A and vitamin E into vesicles was determinated. In both cases higher efficiency was determinated for vesicles with incorporated vitamin A. Higher efficiency for both vitamins was determinated by HPLC. The reason is probably the higher sensitivity of the metod, work in labs with dark glass and preparing individuals samples into vials, which were inserted into the device for individual dosing by injector. The work serves primary evaluation results in view of the vesicular system for use in pharmaceutical application like carrier non-polar vitamins.
Determination of antibiotic residues in soil
Kaprinay Bréda, Boglárka ; Zlámalová Gargošová, Helena (referee) ; Mravcová, Ludmila (advisor)
This master‘s thesis is focused on the optimization of sample preparation and analytical method for the determination of fluoroquinolone. The theoretical part describes the principles of analysis in soil samples, environmental aspects of antibiotic resistance, characteristics of UPLC-MS / MS methods, description of quinolone. The experimental part deals with the identification and determination of fluoroquinolone substance (ciprofloxacin, enrofloxacin) in soil in which manure from poultry litter was incorporated using liquid chromatography with mass spectrometry (MS / MS, triple quadrupole). Internal standard and standard addition methods were used to quantify ciprofloxacin and enrofloxacin. The amount of CIP in the samples ranged from 0.2030 to 12.7088 µg·g-1 and for ENR from 0.2537 to 10.0224 µg·g-1.
Use of capillary electrophoresis to determine a selected group of flavonoids
Tran Xuan, Tiep ; Mravcová, Ludmila (referee) ; Řezáčová, Veronika (advisor)
In recent years, the use of natural medicinal properties of plants has again come to the forefront of interest of the public. Because of their therapeutic properties, these plants are commonly used in alternative treatments for minor ailments. This thesis deals with the determination of polyphenolic acids in extracts from aronia, echinacea, tetradenia and centella. One of the aims of the thesis was to compare the amount of polyphenolic acids in individual plants with their antioxidant properties. The theoretical part includes a general introduction to flavonoids, introduction to polyphenolic acids, introduction to the principles of capillary zone electrophoresis and a summary of selected foreign studies for the determination of flavonoids. An important chapter of the theoretical part is a description of individual plants with an explanation of their possible therapeutic use. The experimental part is devoted to the process of optimization of electrophoretic determination of selected polyphenolic acids and evaluation of their content. It was found that in the extracts six representatives of polyphenolic acids occur in minimal amounts, often below the limit of quantification or detection of the method.
Use of various extraction techniques for the analysis of biochar extracts
Jakubčeková, Kristína ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
Biochar is a material whose properties, composition and impact on the environment are often discussed nowadays. The reason is its application as a soil conditioner. This leads to the need for qualitative as well as quantitative knowledge of its composition. This diploma thesis focuses on the qualitative analysis of biochar leachates processed by various extraction techniques. To approximate the real conditions, six aqueous mediums with different pH values is used, which a solid sample of biochar is exposed to. The prepared leachates are after that processed by extraction techniques, which are solid phase microextraction (SPME), single drop microextraction (HS-SDME), solid phase extraction (SPE) and liquid-liquid extraction (LLE). Analysis of the extracts was performed by gas chromatography-mass spectrometry (GC/MS). The measurements showed that the HS-SDME technique did not show a response. SPE was a rapid technique, but compared to other techniques, it acquired a smaller range of substances. Liquid-liquid extraction, a time-consuming technique, did not obtain as much analytes as SPME. By comparing these applied techniques, the SPME technique is the best choice. The most common determined analytes were those from the group of ketones and carboxylic acids and their derivatives.
The study of metallocene anticancer therapeutics-cells interaction
Bilavčíková, Kristýna ; Mravcová, Ludmila (referee) ; Vašinová Galiová, Michaela (advisor)
There were almost 600 thousand patients in Czech Republic until 2017 and the number keeps rising. Chemotherapeutics used today have lots of undesirable side effects, so scientists around the world are trying hard to find more specific and less cytotoxic drugs. In this bachelor’s thesis, potential drugs based on metallocene with a central atom of Ru, Hf or Zr were studied, always in three different drugs for each element. The permeability and distribution of these drugs into lung cancer cell lines were investigated. These drugs were detected by analysis of solutions and laser ablation with an ICP mass spectrometer. Based on the experiment, the greatest potential was found for the ruthenium-based drug 133, which had the highest permeability and was able to get into the cells in the highest volume.
Ecotoxicological evaluation of selected plastics
Demová, Kristína ; Mravcová, Ludmila (referee) ; Zlámalová Gargošová, Helena (advisor)
The presented bachelor thesis deals with the issue of plastics in the environment and their ecotoxicological evaluation. This topic is currently being brought to the fore due to the development of new, more easily degradable plastics. This is intended to be a solution to the current environmental problem. That is why the aim of this work was to verify the assumption of ecological safety of such plastics. The experimental part focuses on one selected biodegradable plastic - polyhydroxybutyrate, which was evaluated using acute and chronic toxicity tests. The tests were performed in an aquatic arrangement to predict the effect on the aquatic ecosystem. Two organisms were chosen from its representatives, the crustacean Daphnia magna and the plant Lemna minor. The chronic test on the organism Daphnia magna shows the greatest results, which indicates the negative effects of the selected plastic on the tested organism.

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