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The possibilities of assessment of free fatty acids
Hornáková, Miroslava ; Vespalcová, Milena (referee) ; Vítová, Eva (advisor)
This thesis deals with the determination of free fatty acids in natural and processed cheese. In the theoretical part the possibilities of extraction, fractionation and determination of lipid fractions, characterization of fatty acids and various methods of their determination are described, including the determination of free fatty acids. In the experimental part the selected method for determination of free fatty acids was optimized and partly validated; this method was then applied to samples of processed cheese analogues and natural Gouda type cheese. For extraction of lipids from the sample the method according to ČSN 0107 was selected, solid phase extraction (SPE) was used for separation of free fatty acids. The method according to ČSN EN ISO 5509, using methanol solution of potassium hydroxide, was applied for esterification, fatty acids methyl esters were determined by gas chromatography with FID detection.
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Biological effects of various hemp fractions
Vacková, Hana ; Skoumalová, Petra (referee) ; Němcová, Andrea (advisor)
Cannabis is the only plant which contains cannabinoids and thanks to these compounds it has enormous potential. This thesis deals with the analysis of technical hemp. Effects of cannabinoids and methods used for cannabis analysis are discussed in the theoretical part. The experimental part includes spectrophotometric characterization of cannabis, it´s antimicrobial effects and thin layer chromatography analysis. Three sorts of Cannabis sativa L. were analyzed, namely Finola, Fedora and Kompolti. Firstly, the content of polyphenols, flavonoids and antioxidant activity in prepared tinctures were determined. Moreover, antimicrobial test were performed using disk test and turbidity determination. Gram-positive and Gram-negative bacteria and yeast organism were tested. It was found that cannabis tinctures possess good antimicrobial effects. Some of them are comparable with synthetic antibiotics. Finally, thin layer chromatography enabled visualization of cannabinoids in prepared tinctures.
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Detection methods of energetic materials
Procházka, Michal ; Diviš, Pavel (referee) ; Friedl, Zdeněk (advisor)
A research on current methods of detection of explosives and related materials was made. At first the thesis studies methods of detection and analysis of explosives including chromatographic methods (TLC, GC, HPLC, IC), mass spectrometry and its variations, ion mobility spectrometry and infra-red spectroscopy. Next the attention is placed on detection of explosives in solid phase by X-ray detection, nuclear magnetic and quadrupole resonance and thermal neutron activation. Practical applications of these methods are of great importance in this thesis as well as their usage in the counterterrorist fight.
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The use of thin layer chromatography for fractionation of lipids in cheese matrix
Pop, Zdeněk ; Vespalcová, Milena (referee) ; Vítová, Eva (advisor)
This bachelors thesis is focused on the use of thin layer chromatography for fractionation of lipids in the cheese matrix. Milk fat, lipids, fatty acids, the possibility of determination of lipid compounds, thin-layer chromatography and gas chromatography are characterized in theoretical part. In the experimental part the conditions for the fractionation of lipids using thin layer chromatography were optimized, selected validation parameters were evaluated, lipid fractions obtained from the solid-phase extraction were verified and fatty acids in lipid fractions in the sample of processed cheese were quantified. The method according to ISO 1735 was chosen for extraction of lipids from the samples. Lipids fractionation was performed on commercially available plates for thin-layer chromatography. The method accrording to ISO 5509 using methanol solution of boron trifluoride as catalyst was chosen for the esterification of fatty acids. The resulting methyl esters were determined by gas chromatography with FID detection.
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Analysis of bilirubin's relevant photoproducts and their biological significance in the issue of neonatal jaundice
Křepelka, David ; Kozlík, Petr (advisor) ; Zelenka, Jaroslav (referee)
Neonatal jaundice occurs in almost 60% of full-term and 80% of premature babies, where a slightly increased concentration of bilirubin protects against oxidative stress just after birth. When a specific bilirubin level is exceeded in serum (usually above 340 µmol·l-1 ), bilirubin-could induce kernicterus. These negative states are prevented by blue-green light phototherapy (420-510 nm), which converts bilirubin into more polar photoproducts that are more easily excreted via bile and/or urine. Published data have shown that newborns with indicated phototherapy may develop clinical problems later in life (higher incidence of e.g. asthma, allergies, type 1 diabetes was observed at a later age). A possible reason for the occurrence of these diseases is the specific biological activity of photoproducts. This study aims to purify an unknown photoproduct (band P), formed after 8 hours of irradiation of a bilirubin solution with blue light, and to establish a quantitative analytical method for its measurement in relevant matrices. This product was isolated and separated by a thin layer and subsequent column flash chromatography. In the next part, an LC-MS/MS method was developed for quantification of band P. Finally, urine, plasma, and feces samples collected from 15 newborns before and after phototherapy...
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Chemické modifikace bilinových barviv
VOMÁČKOVÁ, Hana
This thesis deals with isolation of phycocyanobilin from cyanobacteria Thermosynechococcus elongatus and its purification with TLC. Purified phycocyanobilin was esterified using Fischer esterification method. The esterification method in this thesis was modified by using dichlormethan as solvent. The results were analysed by HPLC method. Pilot experiments dealing with insertion of esterified phycobilins into self-organized aggregates of bacteriochlorophyll c were carried out.
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Chemo-enzymatic synthesis of antiviral prodrugs
Tupec, Michal ; Stiborová, Marie (advisor) ; Indra, Radek (referee)
Lipases have been widely applied in the manufacture of food products and in some areas of the industry, nowadays they are used in synthetic organic chemistry catalyzing the hydrolytic/esterification reactions under very mild conditions in the field of protecting groups or enantiomer resolution. In this study, the commercial lipase from bacterium Pseudomonas fluorescens was immobilized using the sol-gel process into organosilicate materials with propyl, octyl or phenyl substituents. The highest hydrolytic activity was found in the enzyme on the octyl-derived carrier. The immobilized enzymes differ in their hydrolytic activities on 4-nitrophenyl esters of various lengths. Subsequent experiments revealed quite good pH stability of the enzymes in a buffer (incubations in pH 3 through pH 11), as well as good temperature stability in isooctane (incubations at up to 100 řC). The majority of organic solvents seem to have no substantial effect on the lipase activity. The biocatalytic properties were studied on a model compound from the group of the acyclic nucleoside analogues - 9-(2',3'-dihydroxypropyl)adenine (DHPA). It was found for example that the best acyl donors are vinyl esters, that the lipase shows a preference towards longer vinyl esters, that the reaction proceeds faster in non-polar solvents or that it...
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Interaction of selected cosmetic additives with biotransformation enzymes
Bušovská, Radka ; Hodek, Petr (advisor) ; Smrček, Stanislav (referee)
Substances which cause an endocrine dysfunction have a negative impact on the human body and can be found all around us. One of the main mechanisms of their action is the binding to cell receptors or the inhibition of key enzymes involved in steroid hormone synthesis. In this study, the inhibitory effect of selected perfumes and car air fresheners on the activity of aromatase, the key enzyme of steroidogenesis, was examined. Aromatase converts male sex hormones into the female ones. Inhibition of this enzyme results in decreased estrogen concentrations and may thus affects human fertility. The aromatase activity was examined based on the aromatization reaction of testosterone into estradiol. The formation of estradiol was monitored by TLC method. Based on the results of the pilot study the tested perfumes do not significantly inhibit the aromatase activity, while air fresheners in cars appear to be potential aromatase inhibitors. Keywords: Endocrine dysfunction, steroidogenesis, aromatase, perfumes, air fresheners, TLC, chromatography
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