National Repository of Grey Literature 136 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Monitoring process contaminants in coffee roasting using LC-MS
Ilyushchenkova, Alexandra ; Juglová, Zuzana (referee) ; Diviš, Pavel (advisor)
The bachelor thesis focuses on monitoring changes in the concentration of process contaminants during coffee roasting using liquid chromatography with mass detection. Green coffee was roasted at 220 °C for 14 minutes with two-minute intervals. Samples for analysis were taken from 10. by 24. minutes of roasting. Practical monitoring of the acrylamide’s formation during coffee roasting was not carried out, since it was not possible to detect acrylamide in coffee using a mass detector, even after its derivatization with thiosalicylic acid. The relevant data were taken from other scientific articles, which reported a linear increase in concentration with the roasting time up to the maximum value and a subsequent exponential decrease at the end of roasting. By monitoring 5-hydroxymethylfurfural, it was found that during roasting, this substance is gradually formed in coffee due to the decomposition of carbohydrates, however, with increasing roasting time, the degradation of this substance occurs quite quickly. The concentration of 5-hydroxymethylfurfural was also determined in coffee samples purchased in the trade network. Concentrations of 5-hydroxymethylfurfural in these samples ranged from 0,3 to 0,38 mg/kg, which are corresponded to those reported in other expert studies.
Study of the use of crops for phytoremediation of contaminated soil by pharmaceuticals
Hamplová, Marie ; Zlámalová Gargošová, Helena (referee) ; Mravcová, Ludmila (advisor)
Pharmaceuticals leaking into the environment from wastewater and livestock farms raise concerns about the impact on the ecosystem and human health. Residues of pharmaceuticals present in soil are subject to a number of biotic and abiotic processes, including uptake, translocation and accumulation by plants. The ability of plants to accumulate or degrade pharmaceuticals could have potential applications in the process of 'phytoremediation', where plants and their associated micro-organisms are used to stabilise, degrade or remove contaminants from the environment. In the framework of this thesis, experiments on phytoremediation of drug-contaminated soil by the cover crop oilseed radish (Raphanus sativus L. var. Oleiformis) under controlled conditions were conducted. Soil samples were extracted by ultrasonic extraction, plant samples by QuEChERS method and the final analysis of drugs was performed by UPLC-MS/MS. Oilseed radish produced a large amount of aboveground biomass compared to the other two crops and the presence of drugs had no negative effect on its growth. However, the determined levels of each drug in the soil and in the crop showed insufficient effectiveness of phytoremediation. The accumulation of drugs by the crop was low except for residues of the antidepressant venlafaxine. Therefore, according to these results, oilseed radish is not a suitable crop for phytoremediation of drug-contaminated soil. Experiments were also carried out with the root vegetable radish (Raphanus sativus L. var. Sativus) and carrot (Daucus carota L.) to assess the risk to human health associated with the accumulation of drugs in vegetable roots. The risk has not been demonstrated in terms of the amount of established drugs in the roots. Only the metabolite clofibric acid accumulated to a higher extent and the antibiotic trimethoprim was the most translocated to the aerial parts of the crop. The rate of uptake and translocation of drugs by the plant depended on many factors, as their content varied considerably between drug groups and between parts and types of crops.
Determination of selected phytopharmaceuticals and their metabolites in waste waters
Nevědělová, Klára ; Stoupalová, Michaela (referee) ; Čáslavský, Josef (advisor)
This diploma thesis will be focused on the identification and quantification of selected phytopharmaceuticals ant theri transformation products using separation and spectrometric methods available in the laboratories of ICTEP.
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.
Stability and properties of combined beverages and fruit concentrates
Klatová, Kamila ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
This diploma thesis deals with the stability and basic properties of combined beverages and fruit concentrates. The theoretical part describes the production and use of fruit concentrates. Furthermore, the work deals with anthocyanic pigments and phenolic substances. The principle and instrumentation of liquid chromatography and electron paramagnetic resonance were described. In the next subchapter, the methods of determination of total anthocyanins and phenolic substances were described. The experimental part of the thesis described the determination of soluble solids, viscosity and antioxidant activity. The total content of phenolic compounds were determined by the Folin-Ciocalteua method and the total anthocyanins were determined by the pH-differential method. In the samples were determined cyanidine-3-glucoside and cyanidin-3-galactoside by liquid chromatography.
Preparation and purification of plasmid DNAs
Němeček, Milan ; Španová, Alena (referee) ; Rittich, Bohuslav (advisor)
With the development of therapeutic methods in medicine, like are DNA vaccines and gene therapy increases demand for new processes for the isolation and purification highly pure plasmid DNA. Most often used methods of purification plasmid DNA are chromatographic methods. In experimental part of this thesis was performed isolation of plasmid pUC-19 DNA plasmid via alkalyne lysis. And purification of plasmid was performed by liquid chromatography and agarose gel electrophoresis.
Study of the occurrence of colistin in soil
Veldamonová, Aneta ; Zlámalová Gargošová, Helena (referee) ; Mravcová, Ludmila (advisor)
Colistin is a polypeptide antibiotic used as a "last resort" effective against Gram-negative bacteria. However, increase in its consumption in veterinary medicine in the last 30 years has led to the development of bacterial resistance even to colistin. The application of slurry to soil containing unmetabolized colistin and resistant bacteria poses a risk, because the resistance of bacteria to colistin can be further developed and spread to other components of the environment. Therefore, this work was focused on the creation and optimization of extraction and analytical methods for soil samples containing colistin. Colistin was detected by liquid chromatography in connection with mass spectrometry (HPLC/MS and UPLC/MS/MS). Many extraction solutions have been tested in connection with ultrasonic extraction and purification on various SPE columns, yet colistin has not been successfully extracted from the soil. Colistin was successfully detected only in the slurry extract. The reason why colistin was not detected in soil extracts could be the sorption of colistin on soil organic matter or the formation of complexes of colistin with humic substances.
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.
Study of selected antibiotics sorption on polyhydroxybutyrate
Amrichová, Anna ; Doležalová Weissmannová, Helena (referee) ; Řezáčová, Veronika (advisor)
The bachelor thesis deals with the issue of sorption of antibiotics on microplastics. Antibiotics and microplastics are now a highly studied topic, due to the positive and negative properties. Antibiotics with groups of sulfonamides and quinolones were selected for the experiment. From sulfonamides, sulfamethoxazole and trimethoprim were selected, and from the quinolones, enrofloxacin and ciprofloxacin, which have already been the impetus for some microplastic studies. Biodegradable polyhydroxybutyrate was used as the microplastic. Two experiments were performed in the laboratory. The first aimed to monitor the time dependence of antibiotic sorption on polyhydroxybutyrate, the second the concentration. The concentration dependence was subsequently evaluated using the Freundlich and Langmuir isotherms. The method of liquid chromatography with mass spectrometry was used for analyzes.
Application of separation methods with mass spectrometric detection for the study of degradation products of new polymeric materials
Čumová, Martina ; Vávrová, Milada (referee) ; Čáslavský, Josef (advisor)
Synthetic polymer materials have been a part of human life since the 20th century. A variety of their use had resulted in a growing demand for their mass production, which then led to their increasing accumulation at waste dumps. After their deposition, these materials are exposed to many environmental factors causing their decomposition and subsequent release of the degradation products into the environment. This thesis is focused on the analysis of the photodegradation products from synthetic polymer materials and particularly polyurethane foams modified with the biodegradable fillers. One dimensional GC/MS and two dimensional comprehensive gas chromatography with time-of-flight mass spectrometry (GCxGC/TOF-MS ) were used for the measurements. The most of photodegradation products of polyurethane foams are injurious to health and environment.

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