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Testing of potential capability of chiral ionic liquids with long alkyl chain in capillary electrophoresis chiral separations II
Müllerová, Kateřina ; Jáč, Pavel (advisor) ; Lochman, Lukáš (referee)
Department: Department of Analytical Chemistry Candidate: Kateřina Műllerová Supervisor: PharmDr. Pavel Jáč, Ph.D. Title of the diploma thesis: Testing of potential capability of chiral ionic liquids with long alkyl chain in capillary electrophoresis chiral separations II Chiral ionic liquid (−)-N-dodecyl-N-methylephedrinium bromide (DMEB) was tested as a selector for chiral separations of selected drugs such as chiral quinolones, ketoprofen, and flurbiprofen by capillary electrophoresis (CE). The effect of several parameters on enantioseparation was examined: (i) type and pH of the separation buffer, (ii) type and amount of organic modifier, and (iii) the concentration of DMEB. When using this chiral selector, only the separation of ofloxacin enantiomers was observed, while the enantiorecognition of other chiral model analytes was not successful under the conditions tested. As a next step, a CE method for the assay of levofloxacin was developed to demonstrate the potential of DMEB as a chiral selector in quality control of single-isomer drugs. The best separation was achieved with 20 mM tris buffer of pH 8.5 containing 100 mM DMEB and 20 % (v/v) of acetonitrile as the background electrolyte. The separation took place in 50 µm id fused silica capillary (80.5 cm / 72 cm) at −30 kV with UV detection...
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Analysis of cough-cold preparations by electrophoretic methods.
Kubíková, Drahomíra ; Pospíšilová, Marie (advisor) ; Jáč, Pavel (referee)
In this study, micellar elektrokinetic chromatography method (MEKC) was developed for the determination of paracetamol (PA), caffein (CO), ascorbic acid (AA) and phenylephrine (FE) in a pharmaceutical preparation. Separation was carried out in a fused silica capillary (31,2 cm x 50 m i.d. effective length 21 cm) at 20 kV with UV detection at 190 nm and 265 nm. Optimized background electrolyte (BGE) was 100 mM boric acid containing 100 mM sodium dodecyl sulfate (SDS) as a surfactant and 10 % (v/v) of methanol. pH* 7,8 was found to be optimal (modified by 50 mM sodium tetraborate). Methylparaben (MP) was used as internal standard. This validated method has been successfully applied for the analysis of commercially available pharmaceutical product (Coldrex tbl.).
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Development of capillary electromigration method for the determination of active compounds in silymarin I.
Riasová, Petra ; Jáč, Pavel (advisor) ; Pospíšilová, Marie (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Analytical chemistry Candidate: Petra Riasová Supervisor: PharmDr. Pavel Jáč, Ph.D. Title of diploma work: Development of capillary electromigration method for the determination of active compounds in silymarin I. This diploma thesis deals with development of the method to determine flavonolignans in silymarine using micellar electrokinetic chromatography. The method was optimized by examining a number of experimental conditions, such as concentration of boric acid, concentration of sodium dodecyl sulfate, concentration of cyklodextrins, volume fraction of organic modifier and applied voltage on separation. Ideal conditions for separation were not found by using univariate optimization, so it was applied chemometric approach for the development of separation method. The separation was carried out in a fused silica capillary (internal diameter 50 µm, total length 47,2 cm and effective length 38,7 cm), later in bubble cell capillary (internal diameter 25 µm, internal diameter of bubble cell 125 µm, total length 48,5 cm and effective length 40 cm), with UV detection at 200 and 320 nm. The capillary temperature was maintained at 25řC. Optimal conditions for separation of the flavonolignans were: 178 mM SDS, 15 mM...
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Analysis of Psilocybe constituents I.
Kobrlová, Tereza ; Jahodář, Luděk (advisor) ; Jáč, Pavel (referee)
The goal of this work was to determine the contents of two main alkaloid types of Psilocybe species occurring in the Czech Republic. Correct identification of species was checked by mycology specialist. Qualitative and quantitative determination of substances contained in three collected species of the genus Psilocybe was carried out by LC-MSn (LIT). Samples were mainly collected in the north and northeast Bohemia. Three species of Psilocybe were found. The most found species were P. serbica var. bohemica then P. semilanceata and only one deposit of P. serbica var. arcana. Total of 35 deposits within eighteen locations. From qualitative point of view, the two main alkaloids were confirmed in all samples. Quantitative results for content of psilocin and psilocybin (in this order) are: P. bohemica 0,005 - 0,152 %, 0,000 - 0,048 %; P. semilanceata 0,087 - 0,337 %, 0,000 - 0,005 %; P. arcana 0,018 - 0,031 %, 0,003 - 0,022 %. Results in all locations are similar and rather dependent on the fungi type. Our results are based on dry mass. This work brought fundamental knowledge for future optimisation of analytical methods and assumptions for the project extension of other locations and determination of content of minority substances alongside the content of majority substances.
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Comparison of APSI and ESI ionization for the development of UHPLC-MS/MS method for the determination of steroid compounds estrogens and progestins
Rabatinová, Martina ; Nováková, Lucie (advisor) ; Jáč, Pavel (referee)
In this study a new analytical method for determination of endocrine disruptors is pre- sented. The endocrine-disrupting phenomena is an area of growing concern. Potential ef- fects of endocrine-disrupting pollutants on wildlife and humans has been increased. Since 1980s deformities in fish are observed. Compounds associated to these effects include nat- ural compounds, such es estrogens, progestins and phytoestrogens, synthetic estrogens and a wide variety of organic pollutants, inluding pesticides, surfactants and plasticizers. Among them, estrogens are extraordinary due to their high estrogenic potency, with phys- iological active concentrations ranging from fg/ml to pg/ml. Endocrine disruptors might cause breast cancer in woman, abnormalities in the human reproductive system and differ- ent expressions of biological disorders in wildlife such as hermaphroditism, feminization, and decreased fertility. The presence of numerous endocrine-disrupting compounds in sur- face waters and sediment has been primarily atributed to their incomplete removal in the sewage-treatment process. Determination of these chemicals is required in order to assess their environmental impact. A new ultra high performance liquid chromatography/tandem mass spectrometry method (UHPLC-MS/MS) is presented in this study. The...
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Application of UHPLC with various types of detection in the field of environmental and food analysis.
Rejman, David ; Nováková, Lucie (advisor) ; Jáč, Pavel (referee)
The use of UHPLC with various types of detection in the field of environmental and food analysis Abstract The aim of this work was to inform about possible use of UHPLC instrumentation in connection with various types of detection when chromatographic separating of substances in the field of environmental and food analysis is performed. The next aim was to search and study a number of articles referring to UHPLC methodology, which are at present available in the internet databases ScienceDirect and Web of Science. On the basis of the information from the articles there is a graphic summary in this work relating to the number of found articles and the groups of analysed substances within years. In the introduction of the work van Deemter's, Gidding's and Knox's theories about the efficiency of the chromatographic system are mentioned. These theories are substantial for understanding the principle of chromatographic separation. Following chapters deal with the problems of the development of chromatography in the last decades, especially concerning the length and type of analytical columns, the size of filling particles or the temperature and pressure in the chromatographic system. Now thanks to the development, the columns dimensions are 50 x 1 mm and are filled with particles less than 2 μm in diameter and...
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Development of capillary electrophoresis method for the determination of three pharmacopoeial impurities in indomethacin
Doubková, Dagmar ; Jáč, Pavel (advisor) ; Sklenářová, Hana (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Mgr. Dagmar Doubková Supervisor: PharmDr. Pavel Jáč, Ph.D. Title of Thesis: Development of capillary electrophoresis method for the determination of three pharmacopoeial impurities in indomethacin. This thesis deals with the development of a micellar electrokinetic chromatography method for the determination of indomethacin impurities (4-chlorobenzoic acid, 5-methoxy-2-methyl-3-indolylacetic acid and 3,4-dichloroindomethacin). All separations were performed in a fused silica capillary with 50 µm id; total length 64.5 cm, effective length 56 cm and with extended light path (150 µm id) detection window. 1-naftylacetic acid (10 µg/ml) was used as an internal standard. The separations were carried out at 30 kV. The analytes were detected at the cathodic end of the capillary at 224 nm. A central composite design was applied for the optimization of the separation conditions. The effect of SDS concentration, content of methanol, concentration of phosphate buffer and buffer pH was studied at three levels. The optimized background electrolyte was: 20 mmol/L phosphate buffer (pH 7.57) containing 58 mmol/L SDS and 0% MeOH. The analysis time (with resolution of all compounds Rs ≥ 3.8) was shorter than 10...
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Využití nanokompozitů jako povrchů pro SALDI-MS.
Böhmová, Eva ; Solich, Petr (advisor) ; Jáč, Pavel (referee)
Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization method used in mass spectrometry that is important for the analysis of biomolecules and large synthetic molecules. However, it is difficult to use MALDI for the analysis of small molecules because the matrix ions interfere with their analysis. Several surface-assisted laser desorption/ionization (SALDI) mass spectrometry methods have been developed as a solution to this problem. In this thesis, polylactide (PLA) nanocomposites containing halloysite nanoclay, hydroxyapatite, magnesium oxide, montmorillonite nanoclay, silicon dioxide, silicon nitride, titanium dioxide, and graphitized carbon black (GCB) nanoparticles were examined as surfaces for SALDI. The intensities of the signals of three human medicines: acebutolol, carbamazepine, and propranolol, obtained from these surfaces were compared to the signal intensities obtained from stainless steel MALDI plate without use of any matrix. The signal intensity was only enhanced when nanocomposites containing 30% GCB, 10% silicon nitride, and 10% titanium dioxide nanoparticles and analytes in concentration of 150 ppm were used. These results, together with the fact that PLA is a biodegradable polymer and can be obtained from renewable resources, make these materials potential...
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Peptide Mapping of Biopharmaceuticals Using CE
Kosolapov, Dmytro ; Jáč, Pavel (advisor) ; Khalikova, Maria (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Dmytro Kosolapov Supervisor: PharmDr. Pavel Jáč, PhD. Consultant: PharmDr. Juraj Lenčo, Ph.D. Title of graduation thesis: Peptide Mapping of Biopharmaceuticals Using CE This work focuses on optimization of capillary electrophoresis (CE) method for the peptide mapping. and enzymatic digestion of proteins using trypsin. Myoglobin from equine heart and a reference antibody were used as substrates. Two digestion approaches were compared: a conventional tryptic digestion in solution and digestion with a commercial SMART Digest Trypsin Kit that is based on immobilized trypsin. The digestion was monitored with RP-HPLC. After a short optimization of tryptic digestion, a number of experiments were carried out to determine the optimal conditions for peptide mapping by means of CE. All the measurements were carried out using a PVA-coated capillary of 50 µm internal diameter, effective length of 56 cm and total length of 64.5 cm. Samples were applied hydrodynamically at a pressure of 50 mbar, the separation voltage was 30 kV, the temperature of the capillary was set to 20řC. The analytes were detected with UV-VIS detector at 200 nm. The effect of BGE type and concentration (30, 60, 90, 120, 150 mM formic acid...
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