National Repository of Grey Literature 447 records found  previous11 - 20nextend  jump to record: Search took 0.01 seconds. 
Study of Transfer of Musk Compounds in Abiotic and Biotic Components of Aquatic Ecosystems
Zouhar, Libor ; Hajšlová, Jana (referee) ; Sokol, Jozef (referee) ; Večeřa, Zbyněk (referee) ; Vávrová, Milada (advisor)
This work was focused on the determination of musk compounds in various components of the environment. Synthetic musk compounds are organic substances commonly used as fragrant constituents of detergents, perfumes, cosmetics and other personal care products (PCPs). These compounds contaminate the aquatic environment through municipal wastewater from sewage treatment plants. The result is accumulation of these analytes in the environment and their occurrence in food chain. Synthetic fragrances are commonly detected also in human body; these substances generally belong among relatively new persistent organic pollutants (POPs) because of their persistence, bioaccumulation, and potential toxicity. The aim of this work was to optimize the methods for the determination of selected synthetic fragrances in wastewater (municipal, industrial) and in fish muscle. These analytes were determined in wastewater [the wastewater treatment plant (WWTP) Brno – Modřice, cosmetic manufacturing plant] and in fish Squalius cephalus that had been caught in the river Svratka. The selected analytes (14 substances) originate from the group of nitromusk, polycyclic musk and linear musk compounds. Solid phase microextraction (SPME) [for wastewater samples] and pressurized solvent extraction (PSE) [for fish samples] were used for isolation of analytes from real samples. The identification and quantification of analytes were carried out by high resolution gas chromatography coupled with mass spectrometry detection (GC-MS). The results show that galaxolide (g.L-1) and tonalide (tenths of g.L-1) were polycyclic musk compounds which were found at the highest concentration level in influent and also in effluent samples from the WWTP Brno – Modřice. The most extended nitromusk compound was musk ketone (hundredths of g.L-1). Linear musk compounds were detected in all influent samples (g.L-1). The overall removal efficiency of synthetic musk compounds from wastewater in the WWTP varies within the following ranges: nitromusk compounds 34.4 % – 85.4 %, polycyclic musk compounds 36.7 % – 53.3 % and linear musk compounds 90.5 % – 99.9 %. On the basis of the results it can be stated that wastewater (effluent from the WWTP) is the primary source of musk compounds, especially of the polycyclic ones in the environment. It has been also shown that ultrafiltration used in a cosmetic plant is a highly efficient technology for removing nitromusk and polycyclic musk compounds from industry wastewater. The results from evaluation of the fish contamination by musk compounds show that galaxolide was the substance which reached the highest concentration levels (tens of g.kg-1 l.w.). The results corroborate ubiquitous occurrence of musk compounds in the environment and reduction of using of nitromusk compounds due to their potential toxic properties. It has been shown that the insufficiency of the purifying procedures used in the WWTP Brno – Modřice has a significant influence on the concentration level of polycyclic musk compounds (tonalide, galaxolide) in fish caught from the river Svratka.
Possibilities of elimination of sulfonamides from the aquatic ecosystem
Suková, Petra ; Mravcová, Ludmila (referee) ; Vávrová, Milada (advisor)
This diploma thesis focuses on the determination of sulfonamide antibiotics especially the possibility of elimination of these substances from the aquatic ecosystem. Nowadays, environmental contamination of the pharmaceuticals and their residues is a serious concern. Main sources of this contamination are wastewater treatment plants (WWTPs), where these compounds are not effectively removed by contemporary conventional technology. For this reason, new methods are being developed and tested that could eliminate the number of contaminants entering the environment in this way. There is a possibility to use the potential of the enzymatic system of wood-decay fungi, especially white rot fungi. Six representatives of sulfonamide antibiotics were selected and isolated from the aquatic matrix via solid phase extraction. The final identification and quantification method was high performance liquid chromatography with mass spectrometric detection. Monitoring of the concentration level of selected sulfonamide antibiotics at the inflow and effluent at the Brno-Modřice WWTP was carried out weekly. Moreover, the effectiveness of elimination of selected antibiotics from the aquatic ecosystem by the use of Trametes versicolor wood-decay fungi cultured on a suitable carrier was verified.
Mathematical analysis in mass spectrometry
Vlachová Hutová, Eliška ; Adam, Vojtěch (referee) ; Valla, Martin (advisor)
In this bachelor work, there is theoretically described the principle of mass spectometry and tandem mass spectometry, usage the method in practices and description of functionality of separate analysers. Next, there is also mentioned the description of mass spectrum and the algorithm to its analysis. Practical part of the work describes the creation of analytic tool to evaluate spectrum and following usage of this programming tool for the practical analysis of flavonoid compounds, concretely isoflavonoid.
Analysis of substances released from composite dental material
Fučík, Jan ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
This master's thesis deals with a present problem of alternative dental fillings, which should replace amalgam fillings. Although there are health concerns about these alternative materials, especially resin composite fillings raise concerns, because they release potentionally harmful substances into the oral cavity. Accordingly even this medical device subjects various tests before releasing to the commercial market and one of these tests was carried out according to ČSN EN ISO 10993 and available scientific literature in the experimental part of this thesis. The amalgam controversy, substances used for manufacturing of resin dental fillings and analytical methods are described in the theoretical part of the thesis. In the experimental part of the thesis, 30 days long cumulative extraction experiments were carried out into various extraction mediums in order to assess suitability of new dental resin filling from ADM, a.s. by comparison with commercially available dental material from company GC EUROPE N.V. These samples were analysed by LC-MS and the amount of eluted substances from dental composites to extraction medium was quantified.
Processing and Visualization of Mass Spectrums
Beneš, Ondřej ; Bendl, Jaroslav (referee) ; Martínek, Tomáš (advisor)
One of new techniques in the field of analytical chemistry, which has more and more practical use, is mass spectrometry imaging. With its ability to record representation of substances in samples during the tissue analyze arise problem with a lot of output data which needs to be handled programmatically. The goal of this work is to create an software for processing and visualization data of new standard imzML. As a part of the work, the field of mass spectrometry, primarily MALDI TOF mass spectrometry, is briefly introduced. There are also introduced some methods for mass spectrometry data preprocessing. The work also contains a summary of current state of available software for processing and visualization of mass spectrometry data. With requests from cooperating laboratory a novel software is designed and implemented, which besides the visualization itself, can preprocess the data for example data smoothing with Savitzky-Golay method, internal calibration or peak detection with continuous wavelet transformation. The software was successfully tested on real data sets.
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.
Study of plasma species by mass spectroscopy
Bureš, Michal ; Čáslavský, Josef (referee) ; Čech, Vladimír (advisor)
Plasma polymer films of tetravinylsilane and mixture of tetravinylsilane and oxygen gas were deposited on silicon wafers. Oxygen gas was mixed in tetravinylsilane to improve the compatibility of thin films on glass substrates. Mass spectroscopy was employed during the cleaning of the deposition chamber to check residual gases and process gases, during plasma deposition to monitor neutral plasma species and to follow plasma stability.
The use of GC/MS for the analysis of drugs
Sýkora, Richard ; Opatřilová, Radka (referee) ; Vávrová, Milada (advisor)
This diploma thesis is based on the current issue of the presence of pharmaceuticals in various components of the environment. Concerning the contamination by residues of pharmaceuticals the most affected environment is the aquatic environment where these substances leaks especially from wastewater treatment plants, which eliminate them during the cleaning process only partially. This work is focused on the selected group of pharmaceuticals, non-steroidal anti-inflammatory drugs (salicylic acid, ibuprofen, caffeine, naproxen, ketoprofen, diclofenac) in waste water. For analysis purposes two types of sampling were used and compared: the conventional spot sampling of wastewater and the sampling using passive samplers POCIS. The sampling took place at the inflow and outflow of the wastewater treatment plant in Brno Modřice. The solid phase extraction (SPE) using Oasis HLB columns was used as the extraction method. Extracted sample was derivatized then. Derivatization agents were: MSTFA (N-methyl-N-(trimethylsilyl)trifluoroacetamid) and BSTFA (N, O-bis(trimethylsilyl) trifluoroacetamid). The final analysis was performed using gas chromatography with mass spectrometric detection Time-of-Flight (GC/TOF-MS).
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.

National Repository of Grey Literature : 447 records found   previous11 - 20nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.