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Comparison of HPLC a GC-MS method for pesticide determination in soil
Chalbia Václavíková, Alena ; Kočárek, Martin (advisor) ; Havlík, Jaroslav (referee)
Physical and chemical properties of pesticides may vary significantly. Pesticides can be acidic, neutral or alkaline. Some compounds containing phosphorus, other sulfur, nitrogen or halogens. These atoms can be important for the detection of pesticides. Some of the compounds are volatile, others on the contrary not evaporate, which is also one of the important properties for chromatography. The diversity of pesticides actually makes it impossible to create a universal method, which is very impractical in terms of quality and time determination. Because that pesticides are one of the most chemicals in most countries. In the food and drinking water are limits on pesticides in order to avoid negative impact on public health. For residues in soil or surface water limits are set. (Lutz et al., 2006)
The objective of this thesis is to evaluate the possibility of using two types of chromatographs with different detectors for the analysis of pesticide. Pendimethalin which was chosen for this work, will be analyzed usinga liquid chromatograph with UV detektor and gas chromatography with mass detector. Both this method will be compared as well two extraction methods (Soxhlet extraction and shaking), and two extraction agents (methanol and acetonitrile).
Another point of the work is to provethe hypothesis that, for the determination of pendimethalin in soil is by gas chromatography using a mass spectrometer in comparison with the high performance liquid chromatography time and more expensive, but will achieve a higher yield and a lower detection limit of the pesticide.
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The behavior of herbicides in kale crop and their impact on the quality of the crop
Kadeřávková, Lenka ; Kočárek, Martin (advisor) ; Břendová, Kateřina (referee)
The thesis is focused on the evaluation of the behavior of herbicides in the growth of kohlrabi. The theoretical and general information on pesticides and herbicides on their behavior in the soil, phytotoxicity (plant injury) and vegetables, are presented in the beginning of the thesis.
A central part deals with the differences in behavior of herbicides in soil with active ingredients metazachlor and pendimethalin, their interaction when applied in a combination and how they behave in the soil when applied separately. It also deals with the results of half-life of applied herbicides. Whether among them was a significant difference in the use of adjuvants, and what kind of effect have the irrigation influenced the experiment. It also evaluates the effect of active substances on the expression of phytotoxicity kohlrabi.
The closing part is focused on the statistical evaluation of the particular options of the applied herbicides. Based on the results the hypothesis has been confirmed. The behavior of the active substances in the soil, which have been applied in the form of mixtures, was differed from the applied herbicides separately. It was found that the applied substance in the mixture have a greater effect on weed control in the crop kohlrabi , longer half-life and their effect on the crop plants is manifested phytotoxic.
The significant impact on the overall evaluation has have the irrigation, which should be an integral part of the application process herbicidal compositions and a follow-up care of a vegetation.
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