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Study of retention and separation of pesticides in different modes of liquid chromatography
Dérerová, Tímea ; Kalíková, Květa (advisor) ; Riesová, Martina (referee)
4 Abstract This bachelor thesis is focused on a separation of six pesticides in reversed-phase and mixed-mode high performance liquid chromatography using Atlantis dC18, XSelect CSH C18, XSelect CSH Fluro-Phenyl and Atlantis Premier BEH C18 AX columns. The same manufacturing parameters - column and carrier particle dimensions opened up the possibility of their direct comparison in terms of retentivity and selectivity. The stationary phases were categorized using Walters test, in terms of hydrofobicity, silanol activity and efficiency. The analytes of interest were pesticides with a different mechanism of action in the environment. Two of them contained an acidic functional group that caused their elution at system void volume if pure water was used as aqueous part of mobile phase. For suppression of dissociation of acidic pesticides, the buffers, i.e., 10mM ammonium acetate, pH 4.7 and 10mM ammonium formate, pH 3.0 were used instead of pure water. Tested columns exhibited different retention and selectivity of analytes. For separation conditions optimization, an experimental approach, including changes in mobile phase composition and pH, and separation temperature, was used. Retention time, resolution and peak shape were all dependent on these chromatographic parameters. The retention of tested pesticides...
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