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Electrokinetic chromatography in nonaqueous and mixed solvents: Determination of critical micellar concentration
Hamráková, Katarína ; Křížek, Tomáš (advisor) ; Kubíčková, Anna (referee)
This thesis deals with the investigation of micelle formation following the addition of a surfactant to a background electrolyte in micellar electrokinetic chromatography and the transfer of these systems to nonaqueous and mixed solvents. The addition of organic solvents to the background electrolyte has a significant effect onmicelle formationandhence separation in electrokinetic chromatographyusinga micellar pseudo-stationaryphase. This effect has not yet been studied in depth. Information on the presence and properties of micelles in a given separation system is important for the understanding of separation processes but also for the development and optimization of analytical methods. In this work, the critical micellar concentration (CMC) of two surfactants, sodium dodecyl sulfate (SDS) and cetyltrimethylammoniumbromide (CTAB), was determinedby introducingthem into a mixed environment with non-aqueous solvents, acetonitrile and methanol. The critical micellar concentration was determined from the dependence of three variables on the surfactant concentration in the solution, namely, the effective mobility of the analytes and the viscosity and conductivity of the solution. Prior to the actual measurements of the effective mobility of the analytes, suitable analytes were selected,two which can...
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Determination of glucosinolates in plant materials
Holá, Veronika ; Křížek, Tomáš (advisor) ; Kozlík, Petr (referee)
This diploma thesis deals with the determination of glucosinolates in plant material by capillary electrophoresis and high performance liquid chromatography. The chemical structure, biosynthesis, degradation, and also biological effects of glucosinolates are described. One part of this work also deals with the methods, which glucosinolates in plant materials were determined by. The experimental part describes the separation of intact glucosinolates by capillary electrophoresis and high performance liquid chromatography. Two plant materials were available for the determination of glucosinolates, namely lyophilized rapeseed leaves and broccoli juice. Micellar electrokinetic chromatography using a cationic surfactant was used to determine intact glucosinolates by capillary electrophoresis. After finding the optimal conditions for the separation of intact glucosinolates, it was found that it is impossible to determine these substances in plant samples. The reason was interference from the matrix, which interfered with this determination. While using high performance liquid chromatography under optimal conditions, some of the intact glucosinolates were identified in a rapeseed plant sample. Furthermore, the calibration dependencies of individual glucosinolates were obtained and the recovery and...
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