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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Vývoj, optimalizace a validace analytické metody na stanovení neurotoxinu beta-N-methylamino-L-alaninu ve vodě a sinicích pomocí LC/MS

HOŘEJŠÍ, Karel January 2018 (has links)
This master thesis deals with the development, optimization and validation of an analytical method for determination of neurotoxin -N-methylamino-L-alanine in pond water and cyanobacteria using LC/MS. Firstly, basic parameters of the analytical method developed within authors´s bachelor thesis were verified. Following parameters were selected for verification: selection of suitable MRM transitions, voltage applied to S-lens and F-lens and standardized collision energy. Secondly, the system suitability testing was performed. Thirdly, the analytical method was successfully validated. Then, the testing and optimization of solid phase extraction for analysis of water samples were carried out. The pH of sample solution and composition of elution solution were chosen for the optimization. In addition, the trichloroacetic acid extraction with acid hydrolysis for cyanobacterial samples was carried out too. Finally, both solid phase extraction and trichloroacetic acid extraction were evaluated and applied to the analysis of real samples.
22

Stanovení reziduí léčiv pomocí separačních metod / Determination of drug residuals using separation methods

Vašíčková, Petra January 2010 (has links)
Nonsteroidal anti-inflammatory substances became a very frequently used and constantly evolved group of the drugs, particularly in a human medicine. The risk of their penetration into the environment, especially to the water environment, is rising during the recent years. The diploma thesis is focused on a selection of appropriate separation method and optimization of analytical procedure for the identification and determination of the non-steroidal anti-inflammatory drugs in sewage and surface waters. Salicylic acid, ketoprofen, diclofenac and ibuprofen were chosen from the wide range of NSAIDs as the most widespread agents of this drugs group in the medical practice. The method was optimized and elaborated using the model water samples. This method was used for determination of the analytes contained in the real water samples. Waste water samples were taken from the large-scale wastewater treatment plant in Brno-Modřice and surface water samples were taken from the Highlands river Křetínka. Solid phase extraction (SPE) was used for the real samples treatment and preconcentration, the determination was performed using the high performance liquid chromatography with mass spectroscopy method (LC-MS).
23

Využití kapalinové chromatografie pro stanovení reziduí léčiv / The Use of Liquid Chromatography for Determination of Drug Residues

Dvořáková, Petra January 2012 (has links)
This work is based on the occurrence of drug residues in the environment. This study is focused on the development and optimization methods for determination of selected drugs in the surface water, aquatic sediment and sewage sludge from waste water treatment plant. From the group of drugs were chosen antibiotics. Antibiotics presented in the environment can cause adverse effects including toxic effects, immunity disorders and indirect bioalteration effects. Sulfonamide antibiotics, which are used in the treatment of urinary and respiratory tract infections as well as in the treatment of other infectious diseases, were chosen as a target compounds. Three optimized analytical methods for determination of sulfonamide antibiotics were developed. For the optimization of extraction were tested: solid phase extraction, pressurized solvent extraction, microwave extraction and ultrasonic extraction. For the final analysis was used liquid chromatography with two detectors - diode array detector and mass spectrometer. These optimized methods were applied for the analysis of real samples. The surface water and sediment samples were collected from two Moravian rivers (the Svratka river and the Svitava river). Samples of sewage sludge were collected from waste water treatment plant Brno-Modřice. Fish samples from the Svratka river were also collected. It was observed that all the selected sulfonamide antibiotics are present in real sediment samples (ug.kg-1). Simultaneously presence of some target analytes in real surface water (ug.l-1) and in sewage sludge (ug.kg-1) samples has been confirmed. In samples of surface water from the Svitava river and in fish samples sulfonamide antibiotics were not detected or their concentrations were below the limit of detection.
24

Využití plynové chromatografie s hmotnostně spektrometrickou detekcí pro posouzení kontaminace odpadních a povrchových vod rezidui léčiv / Application of Gas Chromatography with Mass Spectrometric Detection for the Assessment of Drug-residue Contamination of Wastewaters and Surface Waters

Lacina, Petr January 2012 (has links)
This work is based on the current issue of increasing concentrations of pharmaceutical residues in various components of the environment. These new environmental contaminants continuously enter the environment. The most affected environmental component is the aquatic environment. This study is focused on the development and optimization of reliable analytical method, which can determine selected drugs in the aquatic environment (waste waters and surface waters) qualitatively and quantitatively. The target compounds were selected mainly from the group of non-steroidal anti-inflammatory drugs (NSAID): salicylic acid, acetylsalicylic acid, clofibric acid, ibuprofen, acetaminophen, caffeine, naproxen, mefenamic acid, ketoprofen and diclofenac. NSAIDs are one of the most used drugs in Czech Republic. For the final analysis of this study was used the comprehensive two-dimensional gas chromatography with mass spectrometric detection Time-of-Flight (GCxGC-TOF MS). It is a very sensitive and reliable analytical method for trace and ultra-trace analysis. Simultaneously, solid phase extraction (SPE) and derivatization are optimized in this work. Optimized analytical method including SPE, derivatization with MSTFA (N-methyl-N-(trimethylsilyl) trifluoroacetamide) and final analysis by GCxGC-TOF MS were applied successfully for the analysis of real samples. Samples of waste water were collected from the waste water treatment plant in Brno – Modřice and samples of surface water were collected from two river streams Svratka and Svitava in Moravian region. The range of concentrations of selected drug residues varied from one to tens of g/L in wastewater and from tens to hundreds of ng/L in surface waters. The degree of wastewater and surface waters contamination by drug residues is assessed in conclusions of the work. Simultaneously, spontaneous degradation of selected drugs in water and removal efficiency of the wastewater treatment plant is assessed in conclusions of the work. The developed method is usable for monitoring and environmental analysis of water ecosystems. It is usable not only for selected drugs, but even for other organic compounds with similar properties.
25

Studium průniku PBDE a perfluorovaných sloučenin do vodních ekosystémů / Study of Exposure PBDE and Perfluorinated Compounds into Aquatic Ecosystem

Vondráčková, Ilona January 2015 (has links)
In the presented PhD. thesis, problems covering occurrence of polybrominated diphenyl ethers (PBDE) and perfluorinated compounds in the environment were solved. The study was focused on identification and further verification of optimal methods in order to determine PBDEs and perfluorinated compounds sampled from the aquatic ecosystem. Polybrominated diphenyl ethers belong to persistent compounds classified as main pollutants; within the environmental constituents, they have been observed particularly in the last decade. For these studies, there were selected surface water matrices and sediments taken in various localities within the river Svratka basin. The analyses were to demonstrate whether they accumulate and remain in these specific matrices for longer time. There we assessed the congeners of polybrominated diphenyl ethers as follows: BDE-28, 47, 66, 85, 99, 100, 153, 154 and 183. In order to isolate them from matrices, various extraction techniques were used, i.e., ultrasonic extraction, microwave extraction, and pressure solvent extraction. Gas chromatography method with electron capture detection (GC/ECD) was selected for determination. The accomplished studies also assessed basic chemical, physical and environmental characteristics of diphenyl ethers in the environmental constituents. The attention was also paid to perfluorooctanoic compounds (PFOA), (PFOS) and (FOSA); physico-chemical properties of these organic pollutants were characterised and their toxicological and environmental aspects were evaluated. Usability of extraction techniques (ultrasonic extraction, pressure solvent extraction, solid phase extraction) applied to PFCs isolation from sediments samples was assessed. Identification and quantification of these analytes were performed using a high performance liquid chromatography/mass spectrometry method (HPLC/MS). After that, the optimized methods applied to real samples. Surface water and sediments were sampled within the river Svratka basin, in particular, from 19 sampling localities. PBDE occurrence was confirmed in sediments samples from the Svratka river (g.kg-1), PBDE were not detected in the surface water samples, their concentrations were below the detection limit, resp.; perfluorinated compounds were not detected in sediments and water samples at all.
26

Využití moderních separačních a spektrometrických metod k identifikaci lipidomu z biologického vzorku / Modern separation and spectrometric techniques for biological sample lipidom investigation

Havelková, Eva January 2013 (has links)
Modern separation and spectrometric techniques for biological sample lipidom investigation Due recent progress in field of mass spectrometry the lipidomics, part of metabolomics, is increasing its importance for broad fields of biological study. The aim of this study is to test the lipid extraction techniques and to optimize the preseparation and separation of lipids suitable for mass spectrometry detection. The fragmentation patterns of four, the most abundant lipid classes of glycerolipids (PC, PE, TG, DG), were acquired for the proposed system. These patterns were compared with literature. The most appropriate method for extraction was declared technique according Folch based on methanol and chloroform solution. The preseparation due SPE method is very useful tool for lipid determination. The optimized were focused to reach higher recovery especially in polar lipid fraction. Proposed HPLC system is based on methanol with ammonium buffer, water and isopropanol. The testing was done on three columns with different type of sorbents (Gemini, Syncronis and Kinetex). The separation was evaluated according mass spectrometer response, shape and wide of particular analytes peaks. Composition contains 20% of water was determinate as the best and also the best separation was achieved by Kinetex column. The proposed...
27

Voltametrické a amperometrické stanovení nitrofenolů pomocí borem dopované diamantové filmové elektrody / Voltammetric and Amperometric Determination of Nitrophenols Using Boron-Doped Diamond Film Electrode

Karaová, Jana January 2018 (has links)
Presented Ph.D. Thesis is focused on the use of the boron-doped diamond (BDD) electrodes for voltammetric and amperometric determination of selected nitrophenols: 2-nitrophenol (2NP), 4-nitrophenol (4NP), and 2,4-dinitrophenol (2,4DNP). These compounds are listed as "priority pollutants" by United States Environmental Protection Agency (US EPA) due to their negative impact on living organisms and are mainly used in agriculture as plant growth stimulators. BDD electrodes are used for determination of wide range of electrochemically both reducible and oxidisable organic compounds and have become a popular electrode material thanks to its commercial availability and excellent mechanical and electrochemical properties. A differential pulse voltammetric method was developed for the determination of 2NP, 4NP and 2,4DNP at a BDD film electrode using electrochemical reduction and of 4NP and 2,4DNP using electrochemical oxidation. The method was successfully applied for the direct determination of these compounds in drinking and river water in the concentration range from 4×10-7 to 2×10-5 mol.L-1 . To improve the limit of quantification, a preconcentration by solid phase extraction from 100 mL (drinking and river water) and 1000 mL (drinking water) of water samples was used with limit of determination...
28

Rychlé metody analýzy migrantů z materiálů ve styku s potravinami / Fast methods for analysis of migrants from food-contact materials

Vavrouš, Adam January 2020 (has links)
(AJ) Food contact materials pose a risk to human health due to a variety of contaminants which they can release into food. These compounds, migrants, include aromatic hydrocarbons, dialkyl phthalates, bisphenols, printing ink photoinitiators, and perfluoroalkyl compounds. The determination of all these substances can be expensive and time-consuming since universally applicable analytical approaches are not available nowadays. This work attempted to develop methods for the simultaneous determination of migrants from all of the mentioned groups in paper-based food contact materials and fatty food. A total of 68 contaminants were studied in paper products using liquid chromatography and gas chromatography coupled with tandem mass spectrometry detection. All analytes were isolated simultaneously using the modified "QuEChERS" method. This method demonstrated acceptable recovery and repeatability for most analytes in the validation study; LOQs ranged from 1.3 to 220 µg/kg. Analysis of 132 real paper products confirmed the occurrence of almost all studied analytes, which were often present in complex mixtures and at concentrations up to 628 mg/kg. A total of 41 potential contaminants were monitored in fatty foods by liquid chromatography with tandem mass detection. Contamination of the mobile phase by...
29

Rychlé metody analýzy migrantů z materiálů ve styku s potravinami / Fast methods for analysis of migrants from food-contact materials

Vavrouš, Adam January 2020 (has links)
(AJ) Food contact materials pose a risk to human health due to a variety of contaminants which they can release into food. These compounds, migrants, include aromatic hydrocarbons, dialkyl phthalates, bisphenols, printing ink photoinitiators, and perfluoroalkyl compounds. The determination of all these substances can be expensive and time-consuming since universally applicable analytical approaches are not available nowadays. This work attempted to develop methods for the simultaneous determination of migrants from all of the mentioned groups in paper-based food contact materials and fatty food. A total of 68 contaminants were studied in paper products using liquid chromatography and gas chromatography coupled with tandem mass spectrometry detection. All analytes were isolated simultaneously using the modified "QuEChERS" method. This method demonstrated acceptable recovery and repeatability for most analytes in the validation study; LOQs ranged from 1.3 to 220 µg/kg. Analysis of 132 real paper products confirmed the occurrence of almost all studied analytes, which were often present in complex mixtures and at concentrations up to 628 mg/kg. A total of 41 potential contaminants were monitored in fatty foods by liquid chromatography with tandem mass detection. Contamination of the mobile phase by...
30

Chirální analýza syntetických vonných látek ve vodním ekosystému / Chiral analysis of musk compounds in water ecosystem

Švarcová, Lucie January 2014 (has links)
Diploma thesis summarizes available information about chiral analysis of synthetic musk compounds in the aquatic environment. In the theoretical part of the thesis chirality and importance of chiral analysis by means of examples of different environmental pollutants is documented. Further consideration is aimed on musk compounds, their classification, characteristics and their fate in the environment, especially in the aquatic environment. After that methods for chiral analysis of synthetic musk compounds are reviewed. The aim of the experimental part of this diploma thesis was to carry out the determination of thirteen representatives of musk compounds (2-cyclohexylethanol, allylcyklohexylpropionate, Arocet, Aroflorone, Citronellol, Fresco Menthe, Galaxolide, hexyl cinnamic aldehyde, HSA, isoamylsalicylate, isobornylacetate, Lilial and Linalool), out of which some compounds are chiral and some are achiral. For the analysis samples of wastewater from the wastewater treatment plant Brno - Modřice were taken. Target compounds were isolated by solid phase microextraction (SPME) and were subsequently analyzed by gas chromatography with flame ionization and mass spectrometric detection. On the basis of data evaluation the removal efficiency forgiven musk compounds in the wastewater treatment plant was assessed.

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