National Repository of Grey Literature 86 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Evaluation of the properties of new types of zwitterionic stationary phases in HILIC
Nováková, Daniela ; Nováková, Lucie (advisor) ; Chocholoušová Havlíková, Lucie (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Daniela Nováková Supervisor: prof. PharmDr. Lucie Nováková, Ph.D. Title of the diploma thesis: Evaluation of properties of new types of zwitterionic stationary phases in HILIC The aim of this thesis was to compare six new zwitterionic Astra ZWIX columns (3 μm, 2,1 x 100 mm) from Chromservis s.r.o. Five groups of compounds were used for the analysis, namely nucleic bases and nucleosides, nicotinic acid derivates, hydrophilic vitamins, beta- blockers, and phenolic acids. These groups of compounds were also analysed on commercially available columns - BEH Z HILIC, SYNCRONIS, OMEGA SUGAR, BEH HILIC and BEH AMIDE (OMEGA SUGAR 3 μm, 2,1 x 100 mm; other columns 1,7 μm, 2,1 x 100 mm). The investigated parameters were retention time, peak resolution, peak symmetry, and peak width at half height. Optimisation to improve peak separation of nucleic bases and nucleosides, hydrophilic vitamins, and beta-blockers was also carried out. The mobile phase gradient was optimized, as well as the column temperature, and mobile phase flow rate. The selectivity of the columns was found not to differ within the batch. The retention time repeatability condition was met for all analytes on all columns, except for...
Evaluation of the properties of new types of zwitterionic stationary phases in HILIC
Nováková, Daniela ; Nováková, Lucie (advisor) ; Chocholoušová Havlíková, Lucie (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Daniela Nováková Supervisor: prof. PharmDr. Lucie Nováková, Ph.D. Title of the diploma thesis: Evaluation of properties of new types of zwitterionic stationary phases in HILIC The aim of this thesis was to compare six new zwitterionic Astra ZWIX columns (3 μm, 2,1 x 100 mm) from Chromservis s.r.o. Five groups of compounds were used for the analysis, namely nucleic bases and nucleosides, nicotinic acid derivates, hydrophilic vitamins, beta- blockers, and phenolic acids. These groups of compounds were also analysed on commercially available columns - BEH Z HILIC, SYNCRONIS, OMEGA SUGAR, BEH HILIC and BEH AMIDE (OMEGA SUGAR 3 μm, 2,1 x 100 mm; other columns 1,7 μm, 2,1 x 100 mm). The investigated parameters were retention time, peak resolution, peak symmetry, and peak width at half height. Optimisation to improve peak separation of nucleic bases and nucleosides, hydrophilic vitamins, and beta-blockers was also carried out. The mobile phase gradient was optimized, as well as the column temperature, and mobile phase flow rate. The selectivity of the columns was found not to differ within the batch. The retention time repeatability condition was met for all analytes on all columns, except for...
Determination of neopterin and its derivatives by HPLC with fluorescence detection.
Říhová, Lenka ; Nováková, Lucie (advisor) ; Chocholoušová Havlíková, Lucie (referee)
TITLE: Determination of neopterin and its derivates by HPLC with fluorescence detection SUMMARY: Neopterin, a pteridine derivative, is produced in human organism by monocytes or by B - lymphocytes stimulated with interferon γ or interleukine - 2. These active substances (interferon γ, interleukine - 2) are connected with immune system activation. Neopterin measurement in body fluids can therefore serve for monitoring of activation of various components of immune system induced by cytokines. Immune activation occurs for example during many infectious diseases, autoimmune diseases and malignant diseases. Recently the connection between neopterin and 7,8 - dihydroneopterin and intracellular oxidative stress and cell apoptosis was demonstrated in several scientific studies. Values of pteridines probably correlate with certain neurological disesases. Totally reduced form of biopterin serves as cofactor of some enzymes in human organism. In clinical practice the concentration of neopterin, eventually other related substances is expressed as the ratio neopterin / creatinine. This diploma thesis is dealing with the development of an analytical method for the determination of biologically active substances biopterin, 7,8 - dihydroneopterin, 5,6,7,8 - tetrahydroneopterin, neopterin and creatinine by high performance...
Development and validation of HPLC method for the determination of nicotine in spray and in e-cigarette cartridges
Maťátková, Marcela ; Chocholoušová Havlíková, Lucie (advisor) ; Matysová, Ludmila (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Marcela Maťátková Supervisor: PharmDr. Lucie Havlíková, Ph.D. Title of Diploma Thesis: Development and validation of HPLC method for the determination of nicotine in spray and in e-cigarette cartridges The aim of this diploma thesis was the development and validation of HPLC method for the determination of nicotine in mouth spray and in e-cigarette cartridges. The development was based on available methods that deal with HPLC analysis of nicotine and its related compound cotinine. The optimum conditions were found using XTerra® MS C18 column (100 x 4.6 mm, 3.5 µm) with mobile phase acetonitrile : 10mM ammonium acetate pH 9 (20 : 80, v/v). The flow-rate was 1 ml/min and the wavelenght of the detector was set up at 260 nm. Trimethoprim was used as an internal standard. Under these conditions nicotine, cotinine and trimethoprim were separated within 5 minutes. It was impossible to determine cotinine in the analysis of mouth spray and chosen electronic cigarette cartridges due to coelution of used excipients. Therefore the developed HPLC method was validated and system suitability parameters were evaluated only for nicotine. The results of validation demonstrated, that the method provides...
HPLC Determination of Lutein, Zeaxanthine and Betacarotene in Dietary Products
Dvořáková, Petra ; Šatínský, Dalibor (advisor) ; Chocholoušová Havlíková, Lucie (referee)
This rigorous thesis deals with modification of method for separation carotenoids lutein, betacarotene and zeaxanthin borrowed from diploma thesis (Optimization of chromatographic conditions for HPLC determination of chosen carotenoids, Petra Dvořáková, 2009). HPLC with VIS detection is the basic method. This method was modified by gradient elution for compressed time of analysis. Four ways of gradient elution were tested during optimization of new procedure. The second aim of this rigorous thesis is summary of extraction ways for carotenoids published in special literature and proposition of extraction procedures for carotenoids from dietary products. Extraction with organic solvents was used during searching for optimal way for extraction. Simple extraction with organic solvent was tested as basic method, but extraction with previous modification of sample (saponification or acidification of extraction medium) was tested too. In spite of testing of many various ways for extraction and many various organic solvents, there wasn't find optimal and universal extraction way.
Development of MEPS method for UHPLC-MS/MS determination of entecavir in renal ultrafiltrate
Janák, Jaroslav ; Vlčková, Hana (advisor) ; Chocholoušová Havlíková, Lucie (referee)
1 Abstract Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of analytical chemistry Candidate: Jaroslav Janák Supervisor: RNDr. Hana Vlčková, Ph.D. Title of Thesis: Development of MEPS-UHPLC-MS/MS methods for the determination of entecavir in kidney ultrafiltrate. The thesis deals with the development and validation of sample preparation method for determination of entecavir in kidney ultrafiltrate, using techniques MEPS (microextraction by packed sorbent). The previously developed UHPLC-MS/MS method for the determination of entecavir in rat urine has been used for the analysis. Hydrophilic interaction chromatography by column Acquity BEH Amide and isocratic elution were employed. The composition of the mobile phase was acetonitrile and 5 mM ammonium acetate pH 4.0 in the ratio 75:25 (v:v). Entecavir C2 13 N15 was used as the internal standard. Ionization of the analyte was carried out by electrospray in the positive ion mode and triple quadrupole was employed as the detector. Quantification of the analyte was realized by two SRM transitions of entecavir and internal standard method. Based on the MEPS optimization method, porous graphitic carbon suitable for the analysis of polar compounds was selected as the most suitable sorbent. The mixture of acetonitrile and water in a...
Stress testing of estradiol and ethynylestradiol
Mašková, Kateřina ; Chocholoušová Havlíková, Lucie (advisor) ; Aufartová, Jana (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Kateřina Mašková Supervisor: PharmDr. Lucie Havlíková, Ph.D. Title of Diploma Thesis: Stress testing of estradiol and ethynylestradiol This diploma thesis is focused on the implementation of stress testing of two estrogenic hormones estradiol and ethynylestradiol. Both substances have been exposed to oxidation and acid and alkaline pH at increased temperature of 70řC for a predefined time period. The results of these tests should have shown a decrease or an increase of the peak area of estradiol and 17α- ethynylestradiol and a potential formation of degradation products. Peak areas and retention times of degradation products were observed by HPLC. The aim of this thesis was to determine the properties of these hormones under various stress conditions like extreme conditions of production, storage, transport and/or under various external influences. Characterization of degradation products and verification of the suitability of methods used for the analysis of degradation products were also aims of this paper. The method was partially validated. In the experimental part there has been found out that estradiol and ethynylestradiol were stable in water as well as in acetonitrile solution...

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