Search

Charles University, Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Ondrej Guláš Supervisor: Assoc. Prof. PharmDr. Lucie Nováková, Ph.D. Title of Diploma Thesis: Evaluation of separation potential of stationary phases based on porous graphitic carbon. Stationary phases based on porous graphitic carbon (PGC) exhibit many interesting features. For example high mechanical resistance, stability across the entire pH range and excellent high temperature resistance. Moreover, they are significant due to their unique mechanism of retention. Despite all of these positive features and long existence on the market, their broader use in pharmaceutical analysis is still lacking. In our paper we have analyzed 11 groups of drugs, including active pharmaceutical ingredient and its potential impurities. Overall, 67 substances have been analyzed. Each separation on PGC has been optimized in order to achieve the best results. Changes in conditions of separation included testing of several mobile phases, gradient and isocratic elution and testing the effect of higher temperature. The use of gradient elution, with mobile phase consisting of acetonitrile and isopropanol in proportion 1:1 as organic modifier and 0,1% trifluoracetic acid as aqueous part has appeared as the most...

Charles University, Faculty of Pharmacy in Hradec Králové Department of analytical chemistry Candidate: Klára Pružinská Supervisor: Assoc. prof. PharmDr. Lucie Nováková, Ph.D. Title od the diploma thesis: Development of UHPLC method for separation of eight structurally related derivatives of vitamin E The aim of this diploma thesis was to develop UHLPC method for the separation of eight derivates of vitamin E. They include a group of tocopherols and tocotrienols. To achieve the aim ultra-high performance liquid chromatography was used. In process of optimalization the most important thing was the choice of stationary phase, consistence of mobile phase, flow speed, temperature of column and the time of separation. The Ascentis Express F5 Column (100 x 3.0 mm, 2.7 μm), Sigma-Aldrich was the best stationary phase because the separation of all eight derivatives on this column including two problematic pairs: β-T3 with γ-T3 and the pair β-T with γ-T was performed. The mobile phase was a mixture of a methanol with acetonitrile (1:1) and water in the ratio 75:25 with a flow rate 1 ml/min, isocratic elution and PDA and FLR detection. In PDA detection the wavelength was set 290 nm. In more sensitive FLR detection the emission wavelenght was 325 nm and the exciting wavelength of exciting was set on 280 nm....

Charles University, Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Lucia Vasilisková Supervisor: doc. PharmDr. Lucie Nováková, Ph.D. Title of Diploma Thesis: Influence of sample preparation method on occurence of matrix effects in UHPSFC-MS analysis of vitamin E The goal of this thesis was to optimize the chromatographic method for the determination of 8 different isomers of vitamin E that would provide better analysis results than two existing methods; high speed (HS) and high resolution (HR). New Torus stationary phases (SP) were tested (diethylamine, 1-aminoantracene, 2-picolylamine and diol under conditions: CO2:MeOH 98:2, flow rate 2 ml/min, injection volume 2 µl, column temperature 40řC, BPR 12.9 MPa, make-up solvent 0.1% NH4OH in MeOH. The modifiers (ethanol, isopropanol and a 1:1 mixture of acetonitrile/methanol) were tested on the 2-PIC column. The effect of additives in the mobile phase was also compared (0.1% NH4OH, 10mM ammonium formate, 10mM ammonium acetate and 2% H2O). The next part of the thesis describes the development of the sample preparation method to reduce or eliminate the matrix effects. Dilution method was tested using solvents - H2O, 50% acetonitrile (ACN) and 75% ACN. Urine samples were 10, 20, 50 and 100 times diluted by the most...

Charles University, Faculty of Pharmacy in Hradec Králové Department of analytical chemistry Candidate: Lucia Chrenková Supervisor: doc. PharmDr. Lucie Nováková, Ph.D. Title of Graduation Thesis: Optimalization and validation of SPE method for the determination of quercetin and its 9 metabolites in biological material. The aim of this study was to develop and validate a new extraction method for the preparation of biological samples for the determination of quercetin and its 9 metabolites: phloroglucinol, 3,4-dihydroxyphenylacetic acid, homovanilic acid, 3-hydroxyphenylacetic acid, 3-(3-hydroxyphenyl)propionic acid, rutin, quercetin-3-glucuronide, tamarixetin and isorhamnetin. Due to the best retention and subsequent elution of all tested analytes the mixed mode (polymeric ion exchanging) cartridge MAX was chosen. The mixture of methanol and 0.5 % trifluoracetic acid in water (95/5) was chosen as optimal solvent for elution. The combination of 0.01M ammonium formate buffer pH 5.0 and 1% methanol in buffer pH 5.0 were chosen as washing solvent. The determination of quercetin and its 9 metabolites was performed using UHPLC- MS/MS. The best selectivity between the critical pair of analytes with the same molecular weight (tamarixetin and isorhamnetin) was achieved using BEH Shield RP18 column and...

Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Analytical chemistry Candidate: Ivana Kmeťová Supervisor: Doc. PharmDr. Lucie Nováková, Ph.D. Title of Diploma thesis: Identification of phenolic compounds in plant extracts using UHPLC-MS/MS The aim of this Diploma thesis was identification of phenolic compounds in dry lyophilized water extract of leaves of wild strawberry (Fragaria vesca L.) using ultra-high performance liquid chromatography coupled with electrospray tandem mass spectrometry (UHPLC-ESI-MS/MS), advantageous in identification of complex plant samples. Phenolic compounds represent a group of very complex naturally occurring molecules in plants, possessing a wide variety of biological and physiological functions and acting as chemotaxonomic marker substances. This work was focused on flavonoids and related substances. For separation, UHPLC was used instead of more common HPLC due to its much higher separation efficiency that is crucial for successful separation of complex samples. Moreover, UHPLC enabled reduction of analysis time. Determination of structures of phenolics was based on evaluation and comparison of MS and MS/MS spectra in both negative and positive ESI ion modes. Full scan spectra, product ion spectra, neutral loss scans and reconstructed...