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Newly synthesized permanently positively charged monosubstituted beta-cyclodextrin derivatives as chiral selectors in capillary electrophoresis.
Havlíková, Martina ; Bosáková, Zuzana (advisor) ; Čabala, Radomír (referee)
This diploma thesis deals with the application of two permanently positively charged monosubstituted β-cyclodextrin derivatives (PEMEDA-β-CD, PEMPDA-β-CD) as chiral selectors in capillary electrophoresis. Use of PEMPDA-β-cyclodextrin in capillary electrophoresis has not been reported in literature. Properties of PEMEDA-β- cyclodextrin are already known, but its application for separation of amino acid enantiomers has not been published yet. Cyclodextrin derivatives were tested as additives in different buffers of different pH and with eventual addition of organic modifier. As suitable background electrolyte 15 mmol·l-1 borate buffer, pH = 9.5 without organic modifier was chosen. Furthermore the influence of chiral selector on separation and eventual enantioseparation of chosen analytes was evaluated. Addition of cyclodextrin derivatives in concentration range 0.0 - 5.0 was tested. Fourteen anionogenic analytes, including native amino acids, N- blocked amino acids and profens, were detected with UV-VIS detector at optimal wavelength 214, 254 or 280 nm. Both chiral selectors were suitable for enantioseparation of N-boc-D,L-tryptophan, which was baseline separated at concentration of selector as low as 0.5 mmol·l-1 . Tested amino acids blocked with terc-butoxycarbonyl and D,L-ketoprofen were partially...
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Electrophoresis in short capillary with dual detection.
Kaliba, David ; Opekar, František (advisor) ; Jelínek, Ivan (referee)
Capillary zone electrophoresis is an analytical method frequently used in many laboratories for solving various analytical problems. This diploma thesis describes one of many applications of capillary zone electrophoresis using a unique laboratory apparatus composed of a short capillary and dual conductivity/UV detector placed in one detection point of the separation capillary. In the first part of this thesis, the laboratory apparatus was tested by the separation of small inorganic and organic ions. Sodium, potassium, tyramine and histidine ions were used to test the two parts of the dual detector. Experimentally obtained mobilities of these ions were compared with those calculated from the tabulated values. In the second part, the apparatus was used for determination of analytes in samples with more complex matrixces, pharmaceuticals Acylcoffin and B-komplex produced by Zentiva, a.s. One analyte was chosen from each pharmaceutical preparation for determination of its concentration in the preparation, caffeine from Acylcoffine and thiamine from B-komplex. The concentrations were calulated using three different calibration methods and the experimentally obtained values were compared with those specified by the pharmaceuticals producer. Key words: capillary electrophoresis; short capillary;...
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Comparison of contactless conductivity detection and direct UV detection sensitivity for electrophoretic determination of N-acetylaminosaccharides
Malý, Michal ; Křížek, Tomáš (advisor) ; Kozlík, Petr (referee)
is work deals with development and optimization of a method for separation and detection of N- acetylglucosamine and its dimer and trimer using capillary zone electrophoresis with contactless conductiv- ity detection. Separation and detection of these substances is possible if sodium hydroxide is used as back- ground electrolyte. Usage of another electrolyte such as disodium phosphate leads to unacceptable baseline noise level. Optimal conditions of this method are a background electrolyte concentration of 40 mmol dm−3 and voltage of 15 kV. e method is very sensitive to background electrolyte pH, used background electrolyte also causes rapid degradation of the inner capillary wall which is why this method has proven difficult to cali- brate properly. e developed method was compared to an already existing method which uses UV detection. e existing method has lower limits of detection and quantification and is less sensitive to working condi- tions. Limits of detection and quantification of the developed method are 34 µmol dm−3 and 104 µmol dm−3 respectively. Limits of detection and quantification of the method based on UV detection are 7 µmol dm−3 and 21 µmol dm−3 respectively. Limits of quantification are that of the analyte whose detection was the least sensitive which was the dimer in both...
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Characterization of self-assembling molecules and their application in capillary electrophoresis
Hodek, Ondřej ; Křížek, Tomáš (advisor) ; Čabala, Radomír (referee)
This diploma thesis deals with application of newly synthesized α-cyclodextrins derivatives, 2I -O-cinnamyl-α-cyclodextrin and 3I -O-cinnamyl-α-cyclodextrin, in capillary electrophoresis. Their unique feature lies in formation of cyclodextrin aggregates in an aqueous solution by inclusion of phenyl moiety of one molecule into cavity of another one. The influence of addition of 2I -O-cinnamyl-α-CD and 3I -O-cinnamyl-α-CD to background electrolyte (BGE) and its impact on effective mobilities of eighteen selected analytes were tested. Nine analytes were measured in the form of cations (aniline, antipyrine, L-histidine, D,L-tyrosine, D,L- phenylalanine, N-(1-naphtyl)ethylenediamine, 4-nitroaniline, p-aminoaceto-phenon and tyramine) and nine in the form of anions (N-acetyl-D,L-phenylalanine, N-acetyl-D,L-tryptophan, N-benzoyl-D,L-phenylalanine, N-boc-D,L-tryptophan, N-FMOC-D,L-valine, N-FMOC-alanine, N-FMOC-D,L-leucine, D,L-3-phenyllactic acid and (R)-(-)-mandelic acid). Electrophoretic mobilities of cations were tested in BGE at pH 2.2 and anions at pH 8.0. The measurements were conducted at 25 and 50 řC. At the beginning the buffer containing 2.5 mM TRIS was adjusted with phosphoric acid to pH 2.2. However, it was found, that phosphate anions might enter cyclodextrin cavity and disable potential...
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Determination of selected components in human urine with electrophoresis in short capillary.
Makrlíková, Anna ; Opekar, František (advisor) ; Jelínek, Ivan (referee)
Capillary zone electrophoresis is frequently used in various analyses. In this diploma thesis a hydrodynamic sample introduction method controlled by pressure pulse has been proposed for short-capillary electrophoresis. The base electrolyte flushes sample from the loop of a six-way sampling valve and is carried to the injection end of the capillary. At the time when the sample zone reached the capillary, a short pressure impulse is generated in the electrolyte stream, which provides injection of the sample into the capillary. Then the electrolyte flow is stopped and the separation voltage is turned on. The amount of sample introduced to the capillary is controlled by the duration of the pressure pulse. This new sample introduction method was tested in the determination of ammonia, histidine, creatinine, uric acid and hippuric acid in human urine and for rapid screening of the contents of the inorganic ions in cerebrospinal fluid and blood plasma. The determination was performed in a capillary with an overall length of 10,5 cm and two base electrolytes was tested - 50 mM MES + 5 mM NaOH (pH 5,10) and 1 M acetic acid + 1,5 mM crown ether 18-crown-6 (pH 2,40). Using dual detection techniques contactless conductivity and UV spectrometric detection, anorganic and organic substances in the sample could...
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Determination of Lithium in Mineral Waters Using Electrophoresis in Short Capillary.
Makrlíková, Anna ; Opekar, František (advisor) ; Tůma, Petr (referee)
The aim of this study was determination of lithium ion concentration in mineral waters "Vincentka" and "Bílinská kyselka" using capillary electrophoresis with contactless conductivity detection. A specialized laboratory-made apparatus designed for separations in short capillaries was first tested for separation of model solution of common inorganic cations and then for analysis of mineral water samples. Lithium ion concentration was determined using method of standard addition. The results obtained were compared with those obtained from atomic absorption and emission spectroscopy; standard addition method as well as the method of calibration graph were used in spectroscopic methods. A good agreement was obtained between experimentally determined concentrations of lithium and those declared in the labels on the mineral water bottles. Keywords Capillary electrophoresis, contactless conductivity detection, mineral waters, lithium, atomic absorption spectroscopy, atomic emission spectroscopy
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Capillary electrophoresis with dual optical and contactless conductometric detection.
Kadlecová, Tereza ; Opekar, František (advisor) ; Jelínek, Ivan (referee)
This work deals with dual detection of organic and inorganic analytes after separation by capillary zone electrophoresis. In the first part, two types of hydrodynamic sampling are tested. Standard hydrodynamic sampling most often used in laboratory-made electrophoretic apparatus, based on lifting the vessel with the sample, in which the sampling end of the capillary is immersed, and a new method based on increasing the pressure in the sampling vessel without moving the capillary. This sampling procedure minimizes experimenter activity because it is controlled by software. Experimenter only changes vessel containing the sample solution for one with separation electrolyte. The experimental parameters, the sampling time and pressure, are optimized to achieve maximum separation efficiency and adequate detection sensitivity. In the second part of the work, the developed method is tested for the separation of amino-acids in a biological sample (urine).
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Determination of hyaluronan by electromigration methods
Bártová, Adéla ; Mravcová, Ludmila (referee) ; Řezáčová, Veronika (advisor)
This thesis is focused on description hyaluronic acid, characterization of its behaviour in water solutions, its chemical-physical properties and its using in different industrial sectors. The next part deals with possibilities of its analysis. The following section of the thesis is focused on electromigration techniques with special attention dedicated to capillary electrophoretic methods, especially capillary zone electrophoresis. The aim of this thesis is optimization of the method of determination of hyaluronic acid in water solutions by capillary zone electrophoresis.
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