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Use of various extraction techniques for the analysis of biochar extracts
Jakubčeková, Kristína ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
Biochar is a material whose properties, composition and impact on the environment are often discussed nowadays. The reason is its application as a soil conditioner. This leads to the need for qualitative as well as quantitative knowledge of its composition. This diploma thesis focuses on the qualitative analysis of biochar leachates processed by various extraction techniques. To approximate the real conditions, six aqueous mediums with different pH values is used, which a solid sample of biochar is exposed to. The prepared leachates are after that processed by extraction techniques, which are solid phase microextraction (SPME), single drop microextraction (HS-SDME), solid phase extraction (SPE) and liquid-liquid extraction (LLE). Analysis of the extracts was performed by gas chromatography-mass spectrometry (GC/MS). The measurements showed that the HS-SDME technique did not show a response. SPE was a rapid technique, but compared to other techniques, it acquired a smaller range of substances. Liquid-liquid extraction, a time-consuming technique, did not obtain as much analytes as SPME. By comparing these applied techniques, the SPME technique is the best choice. The most common determined analytes were those from the group of ketones and carboxylic acids and their derivatives.
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Development of LC-MS method for determination of selected endocrine disruptors
Chvalkovská, Eliška ; Kučera, Radim (advisor) ; Štěrbová, Petra (referee)
Charles University Phaculty od Pharmacy in Hradec Králové Department of Pharmaceutical Chemistry and Pharmaceutical Analysis Candidate: Eliška Chvalkovská Supervisor: doc. PharmDr. Radim Kučera, Ph.D. Consultant: Mgr. Martin Novák Title of thesis: Development of LC-MS method for determination of selected endocrine disruptors The thesis is focused on the development and optimization of LC-MS method for the determination of twelve endocrine disruptors in amniotic fluid of pregnant women in the third trimestr of pregnancy. There is a suspision that premature births are connected with an increased incidence of endocrine disruptors in amniotic fluid. The analytes were extracted by liquid-liqud extraction with 4-methylpentan-2- on. The analytical method is based on using reverse phase high-performance liquid chromatography with Hypersil C4 GOLD column (2.1 × 100 mm, particles 1.9 µm). For analysis the gradient elution with the mobile phase A (0.5% (v/v) formic acid aqueous solution) and B (0.5% (v/v) formic acid solution in acetonitrile) at a flow rate of 0.5 ml/min, injection 5 µl and column oven temperature 35 řC was used. The high- resolution mass spectrometer Orbitrap Q Exative Plus with atmospheric pressure chemical ionization in positive mode was used to identify and determine the response of...
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Development of LC-MS method for determination of selected endocrine disruptors
Chvalkovská, Eliška ; Kučera, Radim (advisor) ; Štěrbová, Petra (referee)
Charles University Phaculty od Pharmacy in Hradec Králové Department of Pharmaceutical Chemistry and Pharmaceutical Analysis Candidate: Eliška Chvalkovská Supervisor: doc. PharmDr. Radim Kučera, Ph.D. Consultant: Mgr. Martin Novák Title of thesis: Development of LC-MS method for determination of selected endocrine disruptors The thesis is focused on the development and optimization of LC-MS method for the determination of twelve endocrine disruptors in amniotic fluid of pregnant women in the third trimestr of pregnancy. There is a suspision that premature births are connected with an increased incidence of endocrine disruptors in amniotic fluid. The analytes were extracted by liquid-liqud extraction with 4-methylpentan-2- on. The analytical method is based on using reverse phase high-performance liquid chromatography with Hypersil C4 GOLD column (2.1 × 100 mm, particles 1.9 µm). For analysis the gradient elution with the mobile phase A (0.5% (v/v) formic acid aqueous solution) and B (0.5% (v/v) formic acid solution in acetonitrile) at a flow rate of 0.5 ml/min, injection 5 µl and column oven temperature 35 řC was used. The high- resolution mass spectrometer Orbitrap Q Exative Plus with atmospheric pressure chemical ionization in positive mode was used to identify and determine the response of...
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Use of various extraction techniques for the analysis of biochar extracts
Jakubčeková, Kristína ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
Biochar is a material whose properties, composition and impact on the environment are often discussed nowadays. The reason is its application as a soil conditioner. This leads to the need for qualitative as well as quantitative knowledge of its composition. This diploma thesis focuses on the qualitative analysis of biochar leachates processed by various extraction techniques. To approximate the real conditions, six aqueous mediums with different pH values is used, which a solid sample of biochar is exposed to. The prepared leachates are after that processed by extraction techniques, which are solid phase microextraction (SPME), single drop microextraction (HS-SDME), solid phase extraction (SPE) and liquid-liquid extraction (LLE). Analysis of the extracts was performed by gas chromatography-mass spectrometry (GC/MS). The measurements showed that the HS-SDME technique did not show a response. SPE was a rapid technique, but compared to other techniques, it acquired a smaller range of substances. Liquid-liquid extraction, a time-consuming technique, did not obtain as much analytes as SPME. By comparing these applied techniques, the SPME technique is the best choice. The most common determined analytes were those from the group of ketones and carboxylic acids and their derivatives.
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Separation and identification of lipopeptides by chromatography and mass spectrometry
Pravdová, Adéla ; Cvačka, Josef (advisor) ; Kozlík, Petr (referee)
5 Abstract Protein lipidation occupies an important place in the post-translational modification group. It plays an important role in the processes of cell differentiation or synaptic transmission. Changes in the presence of lipidated proteins may in some cases indicate the appearance of human diseases such as Huntington's disease, schizophrenia, or cancer. For this reason, their analysis has become desirable, but also problematic due to its specific characteristics. This work is focused on the development of conditions for measurement of lipopeptides produced by cleavage of proteins containing lipomodification. Two separation procedures were tested, in which the aim of work was to enrich the lipopeptides and remove as many other molecules as possible from the samples. The first test method - phase interface separation, using water and chloroform, was able to concentrate the lipopeptides on the phase interface and separate some of the added unmodified peptides from the mixture. The second method of separation was a solid phase using a C18 stationary phase. As a more suitable solid phase extraction variant, elution with solutions containing acetonitrile with trifluoroacetic acid was chosen as compared to solutions containing isopropyl alcohol. With the modified elution procedure, it was possible to separate...
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