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HPLC determination of silybin diastereoisomers in plasma of laboratory animals
Kolářová, Petra ; Tesařová, Eva (advisor) ; Bednář, Petr (referee)
Silybin is the main component of silymarin, a standardized extract obtained from the seeds of milk thistle (Silybum marianum). Flavonolignan silybin has antioxidant, hepatoprotective, chemoprotective and antitumor activities. Natural silybin occurs as an approximately equimolar mixture of two diastereoisomers - silybin A and silybin B. Analytical separation of these diastereoisomers is possible but preparative separation is complicated. The biological activity of the silybin A is different from the silybin B. Silybin diastereoisomers are mainly conjugated to glucuronides and sulfates in organism. A mixture of both silybin diasteroisomers is used in the majority of reported biological, chemical and pharmacokinetic studies. For the first time, optically pure silybin A and silybin B were used for pharmacokinetic study in this thesis. The object of this work was determination of the concentration of free and total silybin in rats plasma in relation to time. Theoretical introduction describes the current state of the problem of chemistry, pharmacology and pharmacokinetics of silybin diastereoisomers. Second part is focused on the selection of appropriate analytical column, chromatographic method and suitable procedure for preparation of biological samples for the determination of the silybin...
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Optimization and validation of analytical method for determination of selected drugs
Geryk, Radim ; Tesařová, Eva (advisor) ; Janečková, Lucie (referee)
The aim of this work was finding suitable conditions for separation of enantiomers of citalopram and citadiol, optimization of chromatographic system and validation of the analytical method for determination of selected enantiomers in drugs. Drugs are often chiral compounds. In many cases, only enantiomer has required pharmacological effects. Advanced chemical technologies associated with the synthesis, separation and analysis of the individual enantiomers caused an increase of the number of new chiral drugs in the form of single pure enantiomers, the chiral switch. Citalopram is one of the widely used antidepressants of selective serotonin reuptake inhibitors (SSRI). Citalopram is used for treatment of depression, panic anxienty or obsessive compulsive disorder of pathological laughing and crying. The pharmacological activity is associated with the S-citalopram, while R-enantiomer is essentially inactive and even counteracts the activity of escitalopram. Citadiol is a chiral syntetic precursor of citalopram. This thesis was focused on monitoring enantioseparation "behaviour" of selected enantiomers. HPLC method with chiral stationary phases based on macrocyclic antibiotics, cyclofructans and cellulose was applied for enantioseparation of the above-mentioned compounds. The optimized chromatographic...
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Comparison of methods for detection and determination of enantiomers of theanine in HPLC
Šlechtová, Tereza ; Tesařová, Eva (advisor) ; Bosáková, Zuzana (referee)
This thesis focused on optimization of separation methods for underivatized theanine enantiomers on two teicoplanin-based chiral stationary phases and separation methods for enantiomers derivatized by 9-fluorenylmethyloxycarbonyl chloride and dansylchloride. Using these optimized conditions the limits of detection and quantification were calculated. Under optimized conditions were also investigated the contents of theanine enantiomers in green tea and in selected dietary supplement containing L-theanine.
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Optimization of endocrine disruptors determination in wastewater treatment plant sludge and application of the method in environmental samples.
Medková, Jaroslava ; Cajthaml, Tomáš (advisor) ; Tesařová, Eva (referee)
Hormonaly active compounds in wastewaters represent nowdays a serious problem. Proceses currently used in watewater treatment plants (WWTP) are unefficient in removing these compounds from contaminated wastewaters. The compounds are supposed to sorb onto solid sludge elements and sediments. In this work seven endocrine disruptors were detected in the sludge samples from WWTPs. A new sensitive method for detection of seven selected endocrine disruptors (4-nonylphenol, bisphenol A, estriol, 17β-estradiol, estrone, 17α- ethynylestradiol, irgasan) was developed. The method is based on accelerated solvent extraction (ASE), gel permeation chromatography (GPC) and solid phased extraction. For final extract analysis, gas chromatography coupled with mass spectrometry (GC/MS) was used. The efficiency of this method was tested using artificially contaminated sludge and the method was used to analyse real samples from several WWTPs in Czech Republic. The effect of sludge age on detection of individual analytes was assessed as well. The concentrations of endocrine disruptors measured in the samples reached up to 1 µg/g. The results are comparable or higher then those reported in other works and they show the necessity of further research on endocrine disruptors in the environment.
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Hazard analysis of nanoparticles in the workplace environment and design of protective measures against their side effects
Skřehotová, Marcela ; Tesařová, Eva (advisor) ; Mráz, Jaroslav (referee)
The diploma thesis is focused on so called new risks, which currently include the risks associated with various nanomaterials - their production, introduction into practice and use. The paper summarizes the up-to-date knowledge about the characteristics of nanoparticles used and it proposes a procedure to estimate potential consequences of their exposure. The experimental part of the paper is represented by a case study, which introduces the practical application of the proposed procedure aiming at estimated exposure to nanoparticles on the workplace where metal working is executed and resulting occupational risks. The aim of this part of the study was to measure selected parameters of aerosols using a special measuring system working on the principle of laser photometry combined with diffusion charger and detector using Faraday cage. The object of the measurements was to determine the numerical concentration of nanoparticles present in working environment and the representation of size groups of submicron particles. The measurement procedure was designed in accordance with ČSN EN 689, ČSN EN ISO 16000-1 and ČSN ISO 8756 standards and data gained were subsequently interpreted. Afterwards the results were used to design the measures to reduce the risk of health damage when facing chronic inhalation...
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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
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Optimization of separation and quantification of prospective products of big bang
Smitka, Jaroslav ; Tesařová, Eva (advisor) ; Kalíková, Květa (referee)
The thesis is a contribution to research aimed at modeling the conditions of the Big Bang and monitoring possible reaction products. As the starting compounds were selected 2- amino-1-butanol, 3-methoxy-1-propanol, 2-methyl-1-butanol, formamide, some of which were subsequently bombarded by PALS at J. Heyrovsky Institute of Physics, Academy of Sciences. Gas chromatography hyphenated with mass spectrometry and liquid chromatography with UV detection were used for analysis. In GC-MS, calibration of 3- methoxy-1-propanol and 2-methyl-1-butanol was carried out and LOD and LOQ were calculated. Comparison of 3-methoxy-1-propanol and bombarded 3-methoxy-1-propanol did not show the emergence of new products since 3-methoxy-1-propanol was in excess. The found compounds can be more likely identified as impurities present in a solvent or in the individual standards. The optimized HPLC system has managed to separate the three standards. Formamide, which is unsuitable for analysis by gas chromatography, due to its high polarity, however, eluted in all tested systems with system peak (the dead time marker). Nevertheless, the bombarded sample was analyzed for comparison with the original standard. Comparison, however, showed no reaction products in the bombarded sample. Key words: big bang laser sparks formamide...
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Study on stability of triazine based herbicides in water
Petrlíková, Kateřina ; Tesařová, Eva (advisor) ; Janečková, Lucie (referee)
The first aim of this thesis was to find a suitable analytical method for monitoring of stability of four s-triazine herbicides in water samples. Two columns - stationary phases C18, namely products of Waters and Astec were tested in HPLC system. The composition of ACN/H2O mobile phase was changed in the range from 90/10 to 60/40 (v/v). Baseline separation of prometone, propazine and prometryne was achieved on the Astec C18 column with mobile phase ACN/H2O 70/30 (v/v). This separation system was used for the study of stability. The stability of s-triazines was monitored in the period of six weeks. The samples of atrazine, prometone, propazine and prometryne water from water tap. All samples were detected at the wavelength of 221nm. No significant changes were found in the contents of s-triazines in the samples were measured in samples of water - water from Vltava, acidified water from Vltava, water from water tap and acidified water from water tap. All samples were detected at the wavelength of 221nm. No significant changes were found in the contents of s-triazines in the samples.
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Determination of selected pesticides and their metabolites by LC/MS
Kořínková, Petra ; Tesařová, Eva (advisor) ; Trešl, Ivan (referee)
Pesticides are the substances designed for destroying, preventing and controlling of pests and protection of plants. Their wide usage in agriculture causes contamination of ground, surface and drinking water, because wastewater treatment plants are not able to remove them. Mostly used pesticides are triazine based pesticides. However their usage is worldwide reduced because of their negative influences on human health and contamination of environment especially with their metabolites, about their toxicity are no information. A method for determination of triazine pesticides atrazine, cyanazine, propazine, simazine, terbuthylazine and their metabolites hydroxytrazine, desethylatrazine, desisopropylatrazine, hydroxyterbuthylazine a desethylterbuthylazine was developed and validated in this diploma work. The determination was realized by LC-MS/MS with electrospray ionization. LOD ranged between 0.5-3.2 pg/ml and LOQ between 1.5-9.6 pg/ml. A test of stability of the maternal substances of these pesticides was performed, in which temperature was found to have the biggest influence on their degradation. A monitoring of the presence of triazine pesticides and their metabolites in water was carried out in Czech Republic. Low concentrations of the maternal substances in surface water and ground water were...
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Analysis of biologically active substances by capillary electromigration methods
Jáč, Pavel ; Polášek, Miroslav (advisor) ; Tesařová, Eva (referee) ; Jokl, Vladimír (referee)
This thesis deals with the utilization of capillary electromigration methods for the analysis of biologically active substances. In the Theoretical part historical progress, instrumentation and separation mechanisms of different electromigration methods are discussed. In addition brief overviews mapping chiral separation by means of CE and complex-formation for the separation selectivity enhancement are also included. Two final sections of Theoretical part are focused on specific features of method optimization and method validation in CE. Practical part is presented by comments on published papers, which were attached in full text version to Addendum. The results presented in this thesis cover two areas. First area is focused on the utilization of electromigration methods for the analysis of polyphenols in plant materials while second area is dealing with the development, optimization and validation of CE methods for quality control of pharmaceuticals and/or nutraceuticals. The first area of the practical part overviews new trends (papers published between 1999- 2005) in the analysis of polyphenols by CE. The second paper focused on the analysis of polyphenols is an original investigation of new kind of BGE based on complex-forming reagent - sodium tungstate - that was applied in the assay of...
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