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Characterization of new HILIC stationary phases
Vaclová, Jana
Hydrophilic interaction liquid chromatography is a frequently used separation method for analysis of polar compounds. It is an alternative method to reversed-phase chromatography, where these compounds show insufficient or very weak retention. A high number of stationary phases are currently available for HILIC and new ones are still being developed. The aim of this diploma thesis was to characterize and compare three relatively new HILIC columns containing an unmodified silica gel (HILIC-A), aminopropyl modified silica (HILIC-B) and polyhydroxyl chain modified silica (HILIC-N) as stationary phase. Based on the study of the effect of acetonitrile content in mobile phase on the retention of a model set of peptides, a multimodal retention mechanism was demonstrated. Analysis of 18 model analytes with different pKa values showed, that the composition of aqueous part of mobile phase (buffer), more specifically it's concentration and pH value, has a significant impact on retention of ionized analytes and peptides on the studied stationary phases. A significant contribution of ionic interactions to retention was observed on HILIC-B and HILIC-A columns. The retention of basic compounds on the HILIC-B column increased with increasing ionic strength, while it decreased on the HILIC-A column. Increasing the...
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Characterization of new HILIC stationary phases
Vaclová, Jana ; Kozlík, Petr (advisor) ; Kubíčková, Anna (referee)
Hydrophilic interaction liquid chromatography is a frequently used separation method for analysis of polar compounds. It is an alternative method to reversed-phase chromatography, where these compounds show insufficient or very weak retention. A high number of stationary phases are currently available for HILIC and new ones are still being developed. The aim of this diploma thesis was to characterize and compare three relatively new HILIC columns containing an unmodified silica gel (HILIC-A), aminopropyl modified silica (HILIC-B) and polyhydroxyl chain modified silica (HILIC-N) as stationary phase. Based on the study of the effect of acetonitrile content in mobile phase on the retention of a model set of peptides, a multimodal retention mechanism was demonstrated. Analysis of 18 model analytes with different pKa values showed, that the composition of aqueous part of mobile phase (buffer), more specifically it's concentration and pH value, has a significant impact on retention of ionized analytes and peptides on the studied stationary phases. A significant contribution of ionic interactions to retention was observed on HILIC-B and HILIC-A columns. The retention of basic compounds on the HILIC-B column increased with increasing ionic strength, while it decreased on the HILIC-A column. Increasing the...
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Characterization of new HILIC stationary phases
Vaclová, Jana ; Kozlík, Petr (advisor) ; Kubíčková, Anna (referee)
Hydrophilic interaction liquid chromatography is a frequently used separation method for analysis of polar compounds. It is an alternative method to reversed-phase chromatography, where these compounds show insufficient or very weak retention. A high number of stationary phases are currently available for HILIC and new ones are still being developed. The aim of this diploma thesis was to characterize and compare three relatively new HILIC columns containing an unmodified silica gel (HILIC-A), aminopropyl modified silica (HILIC-B) and polyhydroxyl chain modified silica (HILIC-N) as stationary phase. Based on the study of the effect of acetonitrile content in mobile phase on the retention of a model set of peptides, a multimodal retention mechanism was demonstrated. Analysis of 18 model analytes with different pKa values showed, that the composition of aqueous part of mobile phase (buffer), more specifically it's concentration and pH value, has a significant impact on retention of ionized analytes and peptides on the studied stationary phases. A significant contribution of ionic interactions to retention was observed on HILIC-B and HILIC-A columns. The retention of basic compounds on the HILIC-B column increased with increasing ionic strength, while it decreased on the HILIC-A column. Increasing the...
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Vývoj, optimalizace a validace analytické metody na stanovení antibiotika ciprofloxacin ve vodě pomocí LC/MS
VACLOVÁ, Jana
This bachelor thesis deals with the development, optimization and validation of an analytical method for determination of antibiotic ciprofloxacin in water using LC/MS. At first, the development and optimization of the analytical method was performed. The following parameters were selected for optimization: mobile phase composition and injection volume of sample, conditions of electrospray, voltage on S-lens and F-lens, collision energy, maximum trap fill time and number of microscans. Then, the analytical method was successfully validated. Finally, the method was applied for the determination of the antibiotic ciprofloxacin in the layers made from PEEK.
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