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Stability of humic substances
Nováková, Šárka ; Smilková, Marcela (referee) ; Klučáková, Martina (advisor)
This bachelor´s thesis is focused on the study of stability of humic acid. Thesis is divided in two parts, the first part is theoretical. In the theoretical part is dealing with the structure, property and point of humic acid and in the experimental part is dealing with stability of humic acid. The objective of this thesis was to investigate the effect of the extraction agents on stability of humic acid. 1M HCl, 1M MgCl2 and MiliQ water was used like extraction agents. Thermo-oxidative stability was tested trough thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Changes of humic acid that occured after extraction were investigated by FT-IR spektrometry and elementary analysis. The results of the measuring were compared with original humic acid.
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Study on the transport of humic acids through the plant cuticles
Smilková, Marcela ; Záhora, Jaroslav (referee) ; Sedláček, Petr (advisor)
This diploma thesis is focused on foliar fertilization. It is nowadays one of the most widespread types of application of commercial fertilizers. Concern of this thesis is the study of plant cuticles as a thin layer on the leaves. These thin membranes are responsible for regulation of water transport and nutrients. Further function of plant cuticles is the mechanical protection of the outer part of the plant. Plant cuticles were characterized by fluorescence spectroscopy, classical optical microscopy and profilometry. The main aim of this thesis is the optimization and verification of experimental methodology aimed to the transport of commercial humic product through plant cuticles by simple diffusion techniques. The results obtained by presented diffusion techniques of humic product through plant cuticles were correlated with the same diffusion experiments through synthetic membranes with defined pore size and density. The study on transport of commercial humic product was realized in hydrogel medium by two different diffusion methods – non-stationary diffusion technique and diffusion couple. The important part of this diploma thesis is the characterization of supported hydrogel matrix by rheology tests, mercury intrusion porosimetry and scanned electron microscopy. Conclusions of this diploma thesis could be used for improving of efficiency of foliar fertilization.
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Transport of Biomedical Active Compounds Through Porous Membranes
Vašíčková, Kateřina ; Smilková, Marcela (referee) ; Smilek, Jiří (advisor)
This bachelor thesis deals with a study of transport of biomedical active compounds through porous membranes. The main goal is to optimize a penetration method of micellar solutions with a solubilized dye and subsequently with solubilized drug. Cetyltrimethylammonium bromide is chosen as a surfactant and a nile red dye is used as a diffusion and fluorescence probe. Selected active compound is a nonsteroidal anti-inflammatory drug ketoprofen with analgesic and antipyretic effects. The diffusion processes are realized using Franz diffusion cells with polycarbonate membrane with a 2 µm size of poruses. The samples are withdrawn in a chosen time intervals and afterwards evaluated by a fluorescence correlation spectroscopy. Using this method, it is possible to screen the diffusion in time even in nanomolar concentrations of a fluorescence probe chosen. This thesis provides an overview of nile red behaviour in the micellar solutions of surfactant during diffusion processes. The experiment can be extended using an active compound, for instance using a ketoprofen as it is mentioned above.
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Optimalization of experimental method for study on penetration of humic acids into leaves.
Smilková, Marcela ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This bachelor’s thesis is focused on the study of penetration of humic substances trough the plant cuticle. The main objective of the thesis aimed at a literature search on foliar fertilization and transport of substances in the plant leaves. According to the literature search, experimental technique was suggested and tested in order to study penetration of humic substances through the leaf cuticle. The method consists of observation of diffusion transport of humic acids between two inert agarose gels separated by the plant cuticle. Cuticles were prepared by the means of three different isolation procedures.
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