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Analysis of Organic Markers for Identification of Sources of Atmospheric Aerosols
Křůmal, Kamil ; Chýlková, Jaromíra (referee) ; Vávrová, Milada (referee) ; Smolík,, Jiří (referee) ; Večeřa, Zbyněk (advisor)
In this work the organic markers that serve for identification of sources of aerosols are monitored. Theoretic part deals with detailed survey of organic markers emitted from the most significant sources of atmospheric aerosols (biomass combustion, combustion of fossil fuels and traffic) as well as with sampling of aerosols and analysis of organic markers by analytical techniques. Monosaccharide anhydrides (emissions from biomass combustion) and polyaromatic hydrocarbons (emissions from traffic and incomplete combustion) were observed especially. Hopanes and steranes (traffic, coal combustion) and fatty acids (cooking) were next groups of monitored organic markers. Markers were studied mainly in size fraction PM1 because this fraction of aerosols is the most harmful to human health. Aerosols were sampled in two seasons (winter and summer) in two towns in 2009. Higher concentrations of aerosols and organic compounds were found in winter season, which resulted from increased combustion of biomass, coal and other organic material while traffic was the most significant source of aerosols in summer.
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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.
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Influence of PbO and CdO nanoparticles on particular physiological functions in mouse.
Svozilová, Eva ; Vrlíková, Lucie (referee) ; Večeřa, Zbyněk (advisor)
The aim of this bachelor´s thesis is to assess the long-term effects of inhalation of nanoparticles of lead oxide and cadmium oxide on the weight of selected organs of experimental white mice. The selected organs (spleen, liver, kidney, lungs, brain) were successively collected during a period of thirteen weeks. The effect of inhalation of both metal oxides was statistically evaluated. In both study groups of the experiment (PbO and CdO), the relation between organs weight and the length of inhalation and the relation between organs weight and inhalation of differing metal concentrations were evaluated, and results both of the study groups were compared to each other.
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Persistent Organic Pollutants in the Environment of the Southern Moravia Region
Lána, Radim ; Kráčmar, Stanislav (referee) ; Večeřa, Zbyněk (referee) ; Hajšlová, Jana (referee) ; Vávrová, Milada (advisor)
Byla provedena studie bioakumulace POP v potravním řetězci a historických trendů hladin POP v sedimentech Brněnské přehrady. Současné úrovně kontaminantů byly stanoveny v jelci tloušti z řeky Svratky a rovněž byla posouzena hygienická kvalita ryb z rekreačního rybolovu. Současné úrovně POP v terestrickém ekosystému byly posouzeny pomocí analýz jehličí jako přirozeného indikátoru znečištění. Studium jedinců tří druhů dravých ptáků z ČR bylo zaměřeno na zhodnocení kontaminace těchto vrcholných predátorů POP. S pomocí analýz vybraných druhů ryb ze Záhlinických rybníků byl rovněž studován proces bioakumulace. Posouzení parametrů dvou moderních extrakčních technik a jejich využitelnosti pro izolaci POP z různých matric bylo námětem poslední části dizertace.
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Application of Mass Spectrometry for the Determination of Oxidative Stress Markers and Mycotoxins
Čumová, Martina ; Večeřa, Zbyněk (referee) ; Hajšlová, Jana (referee) ; Vávrová, Milada (referee) ; Čáslavský, Josef (advisor)
The first topic presented in the dissertation thesis is determination of isoprostanes as markers of oxidative stress and other compounds affected by presence of oxidative stress. Isoprostanes iPF2-III, iPF2-VI, iPF2-VI, astaxanthin and polyunsaturated fatty acids (PUFA), especially arachidonic acid (AA) were monitored in Atlantic salmon eggs (Salmo salar). Methods for the determination of these compounds have been developed and optimized using chromatographic separation coupled to conventional or mass spectrometric detection. Freshly laid eggs, eyed embryos and non-viable eggs were used to test a general hypothesis that egg viability can be affected by susceptibility to oxidative stress, either through the specific fatty acid concentration and/or the antioxidant capacity of the eggs. Levels of isoprostanes and arachidonic acid (AA) were significantly higher in non-viable eggs than in control (eyed embryos) as well as relative abundance of PUFA. While no difference of isoprostanes was found between freshly laid and control those from the Atlantic stock except iPF2-VI which was observed under the LOQ in the control. Higher levels of PUFA and AA in comparison with the control were observed in the freshly laid eggs. However, the only statistically significant difference was observed in the amount of astaxanthin. Different levels of PUFA and astaxanthin may be related to their biochemical consumption during the development of eggs. This work evaluated potential effect on the viability of eggs Salmo salar due to the presence of oxidative stress. The monitoring of mycotoxins in food and feed was the subject of the second topic. Mycotoxins are secondary metabolites produced by fungi. They are ubiquitous undesirable natural contaminants that are toxic for humans and animals. Today are known more than 500 mycotoxins. However, only few of them are regulated by the European Union. The European Food Safety Authority (EFSA) was asked by the European Commission to provide a scientific opinion on other mycotoxins for which statutory limits could be developed. In this study is proposed simultaneous screening allowing fast, reliable and sensitive approach, identification and quantification of 17 mycotoxins in food and feed sample. The method includes both mycotoxins regulated by the EU and selected mycotoxins required by the EFSA (aflatoxins, deoxynivalenol, nivalenol, zearalenone, fumonisin, ochratoxin A, T-2 toxin, HT-2 toxin, enniatins and beauvericin). Analytes are isolated by the modified QuEChERS method. For separation and target mycotoxins detection, ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC –MS/MS) was employed. The method also allows determination of ergot alkaloids (ergocornine, ergosine, ergocryptine, ergocristine and their respective epimers). The developed method was used either for monitoring mycotoxins and ergot alkaloids in feed and raw materials and barley and malt prepared from it.
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Separation of Azaarenes by High Performance Liguid Chromatography
Kočí, Kamila ; Friedl, Zdeněk (referee) ; Večeřa, Zbyněk (referee) ; Ventura, Karel (referee) ; Šimek, Zdeněk (advisor)
Under the framework of this PhD project, a study on chromatographic behaviour of selected azaarenes on octadecylsilica stationary phases during their separation by reversed phase liquid chromatography was developed. The main goal was aimed at an application of the basic RPLC principles on the retention behaviour of azaarenes including the effects such as peak tailing, peak broadening, irreproducible retention or strong retention on a stationary phase. This study was particularly focused on basic azaarenes, also called acridines, which belong to a group of persistent organic pollutants providing mutagenic and/or carcinogenic activity. The retention patterns were studied on a group of eight acridines that are often present in environmental samples polluted with polycyclic aromatic compounds. The mixture of acridines was separated under isocratic elution conditions on three octadecylsilica stationary phases using two different binary mixtures as a mobile phase. Evaluation of the surface properties of the selected stationary phases was firstly performed, followed by the separation experiments. The structure of the experiments was designed to evaluate the effect of three different factors on the retention behaviour of acridines: properties of a stationary phase, composition of a mobile phase and physical-chemical properties of acridines. The treatment of the results was based on the capacity factor values providing the best fitting and repeatability of data, but other parameters that evaluate thermodynamic and kinetic aspects of the separation process were also given. Simple correlations between the three factors and a character of retention mechanism of acridines on the given separation system were found. Application of this knowledge simplifies an optimisation process and helps to solve common separation problems for acridines, but also for other basic analytes displaying similar physical-chemical properties (Mr and pKa).
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Determination of kadmium content in plant tissue of Norway Spruce and European Beech after application of cadmium oxide nanoparticles
Svozilová, Eva ; Mikuška,, Pavel (referee) ; Večeřa, Zbyněk (advisor)
The aim of this thesis is to monitor cadmium content in needles of Norway spruce and European beech leaves after controlled exposure to cadmium oxide nanoparticles and evaluate the potential risks of such nanoparticles to plants. Needles and leaves were harvested after a one-week and two-week exposure and prior to analysis of cadmium content, they were modified using relevant procedures. Samples were mineralized in nitric acid using pressurized microwave mineralizer and subsequently analyzed by atomic absorption spectrometry (AAS) with electrothermal atomization of cadmium content. Based on the results AAS analysis the transport of nanoparticles into the plant tissue of studied species was evaluated, comparing the content of cadmium in one week and two weeks experiment in the washed and unwashed samples of needles and leaves.
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Cholinesterases inhibited by novichok agents - in silico study of reactivation possibilities
Večeřa, Zbyněk ; Roh, Jaroslav (advisor) ; Holas, Ondřej (referee)
Title: Cholinesterases inhibited by novichok agents - in silico study of reacti- vation possibilities Author: Zbyněk Večeřa Department: Department of Organic and Bioorganic Chemistry Supervisor: doc. PharmDr. Jaroslav Roh, Ph.D. Advisor: PharmDr. Mgr. Tomáš Kučera, Ph.D. Abstract: Substances known as Novichok agents are banned chemical warfare agents, which were developed in Soviet Union between the 1970s and the 1980s. They were brought to the public attention very recently - they were used to po- ison a double agent named Skripal in 2018 and again in 2020 to poison Russian politician Navalny. It is the 4th generation of nerve agents which cause cholinergic syndrome by irreversible inhibition of acetylcholinesterase (AChE), manifesting symptoms such as depression of bronchial tubes, cramps or even paralysis of re- spiratory muscles and depression of the respiratory control centre in the brain. Victim then dies of asphyxiation unless antidotes are administered as soon as possible. Treatment of nerve agents induced poisoning is based on reactivating AChE by oxime compounds which bind themselves with the toxic substance by nucle- ophilic attack on electropositive point of the nerve agent, releasing acetylcholi- nesterase that can continue with function of acetylcholine hydrolysis. The task was to...
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Cholinesterases inhibited by novichok agents - in silico study of reactivation possibilities
Večeřa, Zbyněk ; Roh, Jaroslav (advisor) ; Holas, Ondřej (referee)
Title: Cholinesterases inhibited by novichok agents - in silico study of reacti- vation possibilities Author: Zbyněk Večeřa Department: Department of Organic and Bioorganic Chemistry Supervisor: doc. PharmDr. Jaroslav Roh, Ph.D. Advisor: PharmDr. Mgr. Tomáš Kučera, Ph.D. Abstract: Substances known as Novichok agents are banned chemical warfare agents, which were developed in Soviet Union between the 1970s and the 1980s. They were brought to the public attention very recently - they were used to po- ison a double agent named Skripal in 2018 and again in 2020 to poison Russian politician Navalny. It is the 4th generation of nerve agents which cause cholinergic syndrome by irreversible inhibition of acetylcholinesterase (AChE), manifesting symptoms such as depression of bronchial tubes, cramps or even paralysis of re- spiratory muscles and depression of the respiratory control centre in the brain. Victim then dies of asphyxiation unless antidotes are administered as soon as possible. Treatment of nerve agents induced poisoning is based on reactivating AChE by oxime compounds which bind themselves with the toxic substance by nucle- ophilic attack on electropositive point of the nerve agent, releasing acetylcholi- nesterase that can continue with function of acetylcholine hydrolysis. The task was to...
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