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...

Liquid crystals are widely used in electronics, medicine and other fields. Analytical separations are important in the development of new liquid crystals to control the purity of synthesized substances. The sample analysis is important for detection of impurities formed during synthesis and for determination of chiral purity of the substance. Liquid crystal-forming substances cannot be separated by capillary zone electrophoresis due to the absence of readily ionizable groups. Electrokinetic chromatography is a method in which a suitable surfactant is added to the background electrolyte. The uncharged substances then interact with the electrically charged surfactant to obtain an effective charge. Separation can occur if they interact differently with the added surfactant. Another problem complicating the analysis is the very low solubility of analytes in water. Separations in this work were therefore carried out under non-aqueous conditions in acetonitrile. However, under these conditions a poor repeatability of the migration times of the substances was observed. Therefore, capillaries with differently coated inner walls were used in subsequent measurements. Surface modification should improve the repeatability of migration times. Several types of capillary coating have been tested. Dynamic coating...

The thesis deals with measuring the content of chosen phenolic substances in some specimen of the genera Chenopodium L. and Atriplex L. Two independent analytical methods were used to determine the content of phenolic substances, namely the Micellar Electrokinetic Capillary Chromatography (MECC) method and the High - Performance Liquid Chromatography (HPLC) method. Two cultured species of the genera Spinacia and Atriplex, three freely growing specimen of the genus Chenopodium and three freely growing species of the genus Atriplex were analysed. The analysis concerned the leaves and the inflorescence of these species.The total content of quercetin and rutin was determined by the MECC method. The highest total content of quercetin was found in the leaves of the Garden Orache (4240 mg/kg of dry matter), the lowest total content of quercetin was found in the inflorescence of the Atriplex prostrata DC. (19.6 mg/kg of dry matter). Rutin was only found in four samples, the rest of the samples contained rutin in quantities below the limit of quantification. The highest content of rutin was found in the leaves of the Lamb´s Quarters (868 mg/kg of dry matter).

Capillary electrophoresis often uses complexing agents since the interaction between the analyte and the complexing agent can result in achieving or improving the separation. Examples of such methods can be electrokinetic chromatography or affinity capillary electrophoresis (ACE). ACE is used to determine the complexing parameters. In case of chiral separation, this issue gets complicated, since the parameters of the two analytes (enantiomers) are not completely independent to one another. Therefore, a procedure has been proposed in this thesis, that should always be used to evaluate the complexing parameters of two enantiomers. Statistical evaluation of these parameters was assessed as well. This work also proposes a method that allows to determine the relative migration order of two enantiomers in two different complexing separation systems. The mathematical description of electrophoresis is based on continuity equations, that are inherently nonlinear. However, these equations can be linearized to obtain an approximate analytical solution. There was recently presented a generalized model, that enables inclusion of complete complexing equilibria in the theoretical description of electromigration. Thus, various phenomena, including nonlinear ones, associated with complexation can be predicted. This...

The thesis deals with the content of selected phenolic compounds in some species of the genus Amaranthus, in black elderberry (Sambucus nigra L.) and buckwheat (Fagopyrum esculentum M.). Phenolic compounds are a group of natural compounds exclusively vegetable character. Flavonoids represent only one group of phenolic compounds. Flavonoids show many positive biological effects, in particular act as antioxidants. Natural flavonoids may cause to prevent from coronary- heard diseases and other diseases associated with older age. In recent years the increased attention is paid to flavonoid investigation due to its biological effects. For the determination of phenolic substances there were used two independent analytical methods. There are the high-performance liquid chromatography (HPLC) and micellar electrokinetic capillary chromatography (MECC). The MECC method was used for determination rutin and free quercetin. The highest content of rutin was found in leaves of buckwheat (76,400 mg/kg of dry weight) and the lowest content of rutin was determined in buckwheat hulls. The highest content of rutin was observed in teas from buckwheat leaves and inflorescence. This amount of rutin corresponds with rutin content in more than two pills of Ascorutin (the most favourite flavonoid medicament in the Czech Republic) The HPLC method was used for quantitative determination of phenolic acids. The content of free quercetin was monitored in all samples. No free quercetin was found both in plant material and in samples of teas. The ethanolic extract from the elderberry inflorescence didn´t contain any free quercetin. Free quercetin wasn?t found in any further samples of teas, which were prepared by described methods.