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Determination of acrylamide in coffee by high performance liquid chromatography
Vajdíková, Tereza ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
The bachelor's thesis aimed to optimize the method of determining acrylamide in coffee using high-efficiency liquid chromatography with a diode-array detector. In the theoretical part of the bachelor's thesis, attention was paid to the taxonomic distribution of coffee, it's processing and chemical composition. Part of the theoretical frequency of the work involved describing the formation of acrylamide in coffee and possible methods of determining it. The practical part looked at validating the method, which was used in the analysis of coffee samples. The individual samples of coffee varied in the type of coffee and the societies where the coffee was obtained. Determination of the acrylamide content has been carried out on commercial, franchised, and selective coffees of the arabica species. Finally, the determination of acrylamide was made in the coffee of various types, in robusta and arabica.
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Analysis of drinks sweetened with stevia extracts
Procházka, Václav ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
The steviolglycosides are the natural, sweet substances from Stevia rebaudiana Bertoni. It affect human health positively and its sweetness is 300x stronger than the sweetness of sucrose. That's why it's used to sweetening the commercial products. Because of its potential properties it's good to have an appropriate method to isolate it. High performance liquid chromatography ( HPLC) is based on the separation of analyte between two immiscible phases with high pressure pump and appropriately chosen stationary phase in the column. Than the analytes come out from the column in different retention times. This master´s thesis follows up selection of the best HPLC system for isolation of the main steviolglycosides and its analysis in commercial products. In the theoretical part of the thesis is described the origin, basic characteristics, botanical description, cultivation and affect to the human health of Stevia rebaudiana Bertoni and its use in food industry. There are also concisely characterized the sweet substances contained in the plant, so called steviolglycosides. Than there are given the theoretical basics of high performance liquid chromatography, HPLC instrumentation and its specific applications at sleviolglycosides with the basic chromatographic parameters. The object of the first experimental part was to research the optimum conditions for time and separation effective chromatographic analysis and select the best chromatographic system for isolation of steviolglycosides. In the second experimental part, I have compared and defined the main steviolglycosides (stevioside, rebaudioside A) in nine selected products, commercially available in Czech republic, with the best chromatographic method. In these products was the contain of the stevioside or rebaudioside A confirmed or refused.
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Comparison of the fruits of some honeysuckle varieties in terms of content selected biologically active compounds
Veselý, Ondřej ; Diviš, Pavel (referee) ; Vespalcová, Milena (advisor)
This thesis is focused to the analysis of selected varieties of honeysuckle kamtschatica (Lonicera caerula var kamtschatica) and their comparison in terms of the content of biologically active substances. There were analysed only varieties grown in 2014. Theoretical part elaborates and characterized various parameters of biologically active compounds such as phenolic, anthocyanins and ascorbic acid and possibilities of their determination. Further it briefly surveys Kamchatka honeysuckle, its taxonomic and morphological properties and its nutritional properties. The experimental part of the work was focused on the description of the methods used for the analysis of biologically active substances and their analysis. Polyphenolic compounds and anthocyanin’s were determined spectrophotometrically and vitamin C was determined by high-performance liquid chromatography. The results and varieties were compared with each other. Overall, we can say that the variety with the highest content of all three analysed biologically active substances is a variety Valchová, which had the second highest content of polyphenolic compounds (546.3 mg · 100 g-1 fruits), the third highest contend of ascorbic acid (35.1 mg · 100 g-1 fruits) and the sixth highest content of anthocyanin (170.8 mg · 100 g-1 fruits)
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Comparison of content anthocyanin pigments in selected cultivars of black elderberry and grape
Becková, Eliška ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
The purpose of this thesis is to compare the contents anthocyans in different varieties of European elderberry (Sambucus nigra L.). It was also studied the relationship between the content anthocyans in selected samples of blue grape varieties (Vitis vinifera L.) and position of the track, where the grapes were grown. The theoretical part describes elderberries and grapes in terms of botanical, chemical, and in terms of their using in the food industry. The dominant part of this chapter is to describe anthocyans and possibilities for their determination in the elderberry and grapes. Emphasis has been placed on the pH-differential method and determination by high performance liquid chromatography. The experiments are divided into two parts. The aim of the first experimental part is comparison of the total anthocyanins content in fifteen varieties of elderberry. The performed analysis shows that in terms of anthocyanins content for cultivation of elderberry in the Czech Republic the most suitable varieties are Mammut, Samyl, Reis aus Vossloch and Haschberg. In the second part of the experiments were determined total anthocyanins content in nine varieties of blue grape grown in the Mikulov region. For determination were used HPLC and pH-differential methods, as well as in the first part. The highest content of pigments was found in varieties Alibernet and Neronet. The present study focused on the suitability of the location pointed to vineyard south to southeast orientation plantings. At the end of the experimental part is a comparison of both methods of determination. Method using high performance liquid chromatography to provide very accurate results compared to less demanding pH-differential method of determination. This is recommended only for tentative determination of anthocyanins content in real samples.
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Evaluation of glutathione content in plants as a marker of heavy metals environmental contamination
Borková, Marie ; Stoupalová, Michaela (referee) ; Opatřilová,, Radka (advisor)
Dependence of glutathione concentration on the amount of thallium in the plant was studied. Observed plant was maize (Zea mays) which was divided to two parts – root and overground. Two culture procedures were elaborated where seeds and young seedlings were cultivated in a solution of thallium of concentration 0, 1, 3, 5, 8, a 10 µmol/l. Extraction agents used during extraction were phosphate buffer and solution of ascorbic acid. Determination of glutathione was realized by capillary electrophoresis (CE) and high performance liquid chromatography (HPLC). Diode array detector (DAD) was used in both methods. Quantification of the thallium amount in the plant was done by method of inductively coupled plasma-atomic emission spectrometry (ICP-AES).
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Use of plasma for degradation of ibuprofen in water
Bača, Ondřej ; Landová, Pavlína (referee) ; Mravcová, Ludmila (advisor)
This Bachelor’s thesis deals with the current problem of increasing concentrations of nonsteroidal anti-inflammatory drugs in water. The concentration increase of these drugs is due to rised anti-inflammatory drugs intake in modern era. Wastewater treatment plants are not capable of sufficient elimination of these drugs in wastewater. That leads to contamination of groundwater and surface water. The long-term impacts of these drugs on human health is not fully understood, so it is necessary to develop new methods, which will lead to complete degradation of nonsteroidal anti-inflammatory drugs and other pollutants. Theoretical part of the Bachelor’s thesis focuses on description and properties of nonsteroidal anti-inflammatory drugs and their consumption in the Czech Republic. Furthermore, the paper deals with advanced oxidation processes especially with plasma. This part of the paper also deals with determination of nonsteroidal anti-inflammatory drugs in water. For degradation of ibuprofen was used plasma. During the plasma treatment, samples were taken in regular time intervals, which were afterwards determined by an appropriate analytical method LC-ESI-MS. The results were compared with scientific studies dealing with this topic.
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Multidisciplinary characterization of interactions between oestrogen hormones and their receptors during sperm capacitation.
Bosáková, Tereza
This doctoral thesis was focused on the multidisciplinary characterizatrion of interactions between hormones and their receptors during sperm capacitation, which is the final step in sperm maturation in mammals and the key event to achieve egg fertilization. Three oestrogenic hormones (17β-estradiol (E2), 17α-estradiol (αE2), 17α-ethynylestradiol (EE2)), which are part of environmental pollution, were selected for the study. These hormones are called endocrine disruptors as they can cause disorders of the hormonal system in animals, thereby adversely affecting physiological processes, including reproduction. A new analytical HPLC-MS/MS method was developed for monitoring of concentration changes of oestrogens (E2, αE2 and EE2) during time-dependent capacitation of mouse and rat sperm in vitro. For individual oestrogens, the concentration dependences of free, unbound hormone on the capacitation time were measured for three concentrations of individual hormones (200, 20 and 2 μg/L). The obtained concentration data were converted into values of relative concentrations, which were subjected to kinetic analysis. Kinetic models were proposed for the interaction of individual hormones with sperm, which were described by a system of differential equations with optimization of rate constants and molar...
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Development of analytical methods for determination of phosphorylated components of bacterial cell membranes
Mikulecká, Jana ; Čabala, Radomír (advisor) ; Feltl, Ladislav (referee)
Phospholipids are dominant components of bacterial cell membranes, where they create double layers. Bacteria differ in their phospholipid composition determination of which can help in identification of important groups of microorganisms. Phospholipid composition of bacteria is influenced by many environmental factors, therefore its variation can be observed within one bacterial stem also. Because of its simplicity, thin layer chromatography is usually applied to identification and determination of bacterial phospholipids. Disadvantage of this method are the high demands of time, carefulness and skills of the analytical personnel. The increasing interest in the phospholipid double-layer promotes the detailed investigation of their fatty acid composition because the more detailed analyses allows for more information yield about bacteria. Gas chromatography hyphenated with mass spectrometry seems to be the best choice for these purposes. Fatty acid identity and total fatty acid content in phospholipid molecules could be determined by this method. Additionally, number, position and isomerism of double bonds and presence of other functional groups on hydrocarbon chain could be determined. Whereas a suitable and...
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Targeted analysis of eicosanoids by LC/MS
Moravcová, Marie ; Kuda, Ondřej (advisor) ; Kozlík, Petr (referee)
Eicosanoids represent large group of biologically active lipid metabolites syntesized from polyunsaturated fatty acids that play an important role in many physiological processes. To describe complex metabolism of these compounds, analytical methods including extraction from a biological sample using solid phase extraction and liquid chromatography coupled with mass spectrometer detection were used. Solid phase extraction of biological samples was optimized on four types of reverse phase columns of which column Strata X 60 mg/3 ml, 33 um (Phenomenex , USA) was the most effective. Also, alternative solid phase extraction of eicosanoids using columns with ion exchange sorbents and a column with normal phase were tested, but proved to be unsuitable for targeted analysis of eicosanoids. The extraction method yielding the best results - Strata X 60 mg/3 ml, 33 µm (Phenomenex, USA) was used for the separation of eicosanoids from mouse gonadal fat samples. Eicosanoids were analyzed by liquid chromatography and the separation mechanisms were tested on three UPLC core-shell columns of different lengths (50 mm, 100 mm, 150 mm). The most effective separation of prostaglandin E2 and prostaglandin D2 was achieved using the longest column Kinetex 150 mm × 2,1 mm, 2,6 µm. Furthermore, ionization parameters, such...
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Chromatograhic characterization of chiral and achiral separation systems
Kučerová, Gabriela ; Tesařová, Eva (advisor) ; Čabala, Radomír (referee) ; Ševčík, Juraj (referee)
Dissertation thesis is a 5-publications' collection concerning characterization and application potential of cyclodextrins, polysaccharides and macrocyclic antibiotics based chiral stationary phases. The effects of stationary phase and mobile phase are studied. This approach ensures the complex insight into separation systems studied. Systems with different nature of chiral selector were studied by HPLC. Namely, macrocyclic antibiotics and derivatized polysaccharides were used for experiments. Former ones provided better results for enantioseparation of non-coded amino acids than latter ones. Dynamic coating procedure was used for preparation of a new chiral stationary phase. Characterization of new cationic cyclodextrin based chiral stationary phase was performed. Linear free energy relationship method was used for characterization of two different separation systems, i.e. newly prepared stationary phase and commercially available stationary phase. Based on results obtained, newly prepared stationary phase showed better results for separation of different achiral groups of analysts. New stationary phase prepared by dynamic coating was compared with chromatographic system, in which the chiral selector was used as a mobile phase additive. The chiral selector used for the two different approaches was...
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