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Studz of direct and indirect plasma application on onion seeding bulbs
Krejsová, Lenka ; Enev, Vojtěch (referee) ; Krčma, František (advisor)
Nowadays, agriculture is based on conventional methods that involve the application of pesticides, agricultural chemicals and fertilizers. These substances have a negative impact on nature and human health, so more environmentally friendly methods are being sought. This thesis deals with the analysis of fragrances in onions treated with plasma before planting. The treatment was carried out to see if it would improve onion growth while maintaining or increasing the fragrance content. The theoretical part deals with the soil and it is characterization methods, plasma, quantitative and qualitative methods for the determination of volatile substances. It contains the principles of UV-VIS spectrometry, atomic absorption spectrometry (AAS), mass spectrometry (MS) as well as tandem connection of gas chromatography with mass spectrometry (GC–MS). The experimental part was carried out over a period of three years at 22 sites. The preparation and analysis of soil samples are described, which was also evaluated. Furthermore, the procedures for treating the bulbs with corona discharge and plasma-activated water before planting were described. In total, four treatment variants were carried out and bulbs from the fifth variant were not additionally treated. Each treatment variant was planted in four replications of ten bulbs each. Twenty selected grown onions from one site were individually converted to liquid samples and the saturated vapor was analysed by proton transfer reaction time of flight mass spectrometry (PTR–TOF–MS). Thanks to this analysis, the concentrations of volatile substances were determined. Some samples were analyzed by gas chromatography with mass spectrometer as detector to identify the compounds. Subsequently, the data were processed and evaluated. From the results obtained, it is evident that plasma treatment can be useful for the treatment of onions in agriculture, because it confirmed harvest increase without decrease of fragrances concentrations. Thus, it is necessary to carry out experiments on a larger scale in the future.
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Analysis of aromatic compounds in plasma treated onion
Krejsová, Lenka ; Kozáková, Zdenka (referee) ; Krčma, František (advisor)
This bachelor thesis deals with the analysis of fragrances in onions, which were exposed to plasma before planting. The adjustment was made to see if onion growth and yields would improve. The theoretical part deals with the quantitative and qualitative methods for the determination of volatile substances. It contains the principle and instrumentation of mass spectrometry as well as the tandem connection of gas chromatography with mass spectrometry. In the experimental part, a liquid sample was obtained by pressing. After 60 minutes, saturated vapors were analyzed by reactive ionization mass spectrometry (PTR-MS). Thanks to this analysis, the concentration of volatile substances was determined. Some samples were analyzed by gas chromatography with mass spectrometer as detector to identify the compounds, because PTR-MS does not allow distinguishing of isomers. Subsequently, the data were processed and evaluated. From the gathered obtained it is clear that the plasma treatment has an effect on the fragrances concentrations. After six months of storage, the presence of some volatile substances increased due to increased biological activity.
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Analysis of aromatic compounds in plasma treated onion
Krejsová, Lenka ; Kozáková, Zdenka (referee) ; Krčma, František (advisor)
This bachelor thesis deals with the analysis of fragrances in onions, which were exposed to plasma before planting. The adjustment was made to see if onion growth and yields would improve. The theoretical part deals with the quantitative and qualitative methods for the determination of volatile substances. It contains the principle and instrumentation of mass spectrometry as well as the tandem connection of gas chromatography with mass spectrometry. In the experimental part, a liquid sample was obtained by pressing. After 60 minutes, saturated vapors were analyzed by reactive ionization mass spectrometry (PTR-MS). Thanks to this analysis, the concentration of volatile substances was determined. Some samples were analyzed by gas chromatography with mass spectrometer as detector to identify the compounds, because PTR-MS does not allow distinguishing of isomers. Subsequently, the data were processed and evaluated. From the gathered obtained it is clear that the plasma treatment has an effect on the fragrances concentrations. After six months of storage, the presence of some volatile substances increased due to increased biological activity.
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