National Repository of Grey Literature 108 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Determination of pesticides enantiomers in water
Šlechtová, Tereza ; Tesařová, Eva (advisor) ; Lokajová, Jana (referee)
This Barchelor's project deals with chiral herbicide mecoprop and its determination by high-performance liquid chromatography method with teicoplanin based chiral stationary phase. The teoretical part focus on basic facts conserning chirality, chiral pesticides and problems related to their usage and effects to the enviroment. It also involves the ways of their determination by the above mentioned method and gives several examples of previous separations. The experimental part is based on method optimalization and determination of changes in mecoprop enantiomeric ratio in various water samples during different storage conditions.
Optimization of HPLC separation of penicillin derivatives
Šímová, Veronika ; Kalíková, Květa (advisor) ; Tesařová, Eva (referee)
Penicillins are part of β-lactam antibiotics, which are wide spread in human and veterinary medicine. The aim of this bachelor work was to develop and to optimize HPLC method for separation of four derivatives of penicillin - amoxicillin, 4-hydroxyphenoxymethylpenicillin, benzylpenicillin and phenoxymethylpenicillin. The reserved phase HPLC with octodecyl stationary phase was used in this work. The baseline separation of all analytes was not obtained in isocratic elution. For this reason, the gradient elution was examined on the baseline resolution of all analytes was achieved and the analysis time did not exceed 22 minutes. The stability of methanolic solutions of penicillins was tested during eight days. Key words: HPLC, antibiotics, derivatives of penicillins, reverse mod, stability
Use of chiral stationary phases based on teicoplanin and teicoplanin aglycone for enantioseparation of FMOC-derivatized amino acids.
Repko, Pavel ; Bosáková, Zuzana (advisor) ; Tesařová, Eva (referee)
In this work, an enantioselective HPLC method with UV and fluorimetric detection was developed and subsequently optimized for chiral separation of four aminoacids (D/L-alanine, D/L-valine, D/L-leucine, D/L-isoleucine) in native and particularly in derivatized form with an emphasis on enantioseparation of D-analogues. Retention and enantioseparation behavior of studied analytes was investigated on three chiral stationary phases based on teicoplanin (Chirobiotic T, Chirobiotic T2) and teicoplanin aglycone (Chirobiotic TAG). At the Chirobiotic T column, enantioseparations of underivatized aminoacids were performed with UV detection at 205 nm in the mobile phases methanol/water with different volume ratios. Baseline separation of L- and D-forms was achieved, however, the sensitivity of detection was very low. In order to increase detection sensitivity, derivatization of aminoacids was performed using 9-fluorenylmethyl chloroformate (FMOC-Cl) and the derivatization procedure was monitored on Chirobiotic T column with fluorimetric detection (λEx = 254 nm, λEm = 314 nm) in a buffered mobile phase methanol/0.5% TEAA buffer, pH 6.0 40/60 (v/v). In terms of derivatization, volume ratio D/L-aminoacid/derivatization agent 1/1 with ten times higher concentration of derivatization agent was found to be the most suitable....
Monitoring of the occurence of Cyanobacteria in the Seč water resevoir by analytical methods
Štangelová, Pavla ; Tesařová, Eva (advisor) ; Cajthaml, Tomáš (referee)
Cyanobacteria are one of the oldest living organisms on the planet Earth. They are able to survive in different conditions under various conditions, almost in all habitats. The growth of cyanobacteria is affected by the amount of nutrients present in the environment, especially nitrogen and phosphorus, and by the climatic conditions. In larger quantities cyanobacteria began to spread in past few decades due to human activities. As a result of excessive use of fertilizers and washing nutrients from the soil is human-caused eutrophication and expansion of the so-called "water bloom". The presence of cyanobacteria in water is monitored using various analytical methods. The occurrence of cyanobacteria on the water reservoir Seč was determined by fluorimetric detection of pigment c-phycocyanin in samples of natural waters and compared with chlorophyll a content in these samples. Key words: cyanobacteria, c-phycocyanin, chlorophyll-a, fluorimetry
Streptomycetes surface growth and differentiation on inert microbeads- morphology and proteome study
Tesařová, Eva ; Weiser, Jaroslav (advisor) ; Lichá, Irena (referee)
Streptomyces, filamentous Gram-positive bacteria are producers of more than 70% of antibiotics used in human therapy and agriculture. They are remarkable because of their complex life cycle (morphological differentiation) which leads to a formation of dormant spores able to survive unfavorable living conditions and allowing long-term survival of the organism. Soil represents their mostly natural living environment. In laboratory conditions they are cultivated in liquid media or on agar. We have developed in our laboratory two phase cultivation system which allows quantitative and reproducible preparation of samples for proteomic, transcriptomic and metabolomic analyses of Streptomycetes differentiation. The system is composed of inert micro- beads submerged in liquid medium. We used two types of micro-beads in our studies, glass and zirconia/silica beads. We followed the surface growth and differentiation of Streptomycetes on both types of beads using optical and electron microscopy (SEM) techniques. We observed major growth and higher antibiotic production on glass beads. Another difference we observed was in size and shape of colonies. In further research, using comparative proteomics, we attempted to identify proteins which might be responsible for recognition and adhesion of Streptomycetes to...
Chlorophenols in the environment
Jíšová, Tereza ; Tesařová, Eva (advisor) ; Pavlík, Milan (referee)
Chlorophenols belong to major environmental pollutants and are characterized by their considerable toxicity, persistence and bioaccumulation. For their bactericidal and fungicidal properties have multiple uses. They are readily formed during water chlorination process and cause sensoric defects of drinking water. Thus they are posing a serious health hazard. Chlorophenols also occur in nature in minor amounts due to natural activity. The presence of chlorophenols in water samples is determined by various analytical methods. In this work, emphasis is placed on their determination by gas chromatography. The model assay was performed for 2-chlorophenol and 4-chlorophenol using derivatization and subsequent extraction with a final analysis by gas chromatography with electron capture detection. The limit of detection for 2-chlorophenol was 2.47 μg/l for 4-chlorophenol 3.14 μg/l. Key words: Chlorophenols, determination chlorophenols, degradation, toxicity
Determination of enantiomers of amino acids by HPLC
Michalčíková, Regina ; Tesařová, Eva (advisor) ; Janečková, Lucie (referee)
This Bachelor's thesis deals with determination of amino acids enantiomers, namely alanine in the experimental part, by high performance liquid chromatography using chiral stationary phases based on teicoplanin. The theoretical part is focused on summarizing the fundamental issue of chirality and chiral amino acids in foods, the characteristics of high-performance liquid chromatography, as one of the most appropriate methods to enantioseparation amino acids, and description of the methods of derivatization, which are used in determination of enantiomers of amino acids. The experimental part deals with the separation of alanine enantiomers, with the choice of the best separation system for the separation and determination of D-and L-alanine in fruit juice.

National Repository of Grey Literature : 108 records found   previous11 - 20nextend  jump to record:
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1 TESAŘOVÁ, Eliška
7 Tesařová, Eva
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