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Study of plasma effects on quinine solutions
Procházková, Michaela ; Dzik, Petr (referee) ; Kozáková, Zdenka (advisor)
This diploma thesis focuses on quinine solutions and quality of these solutions after applying plasma discharge. These electric discharges can be used to destroy some substances from the water. The theoretical part is focused on description of electric discharges in liquids and on the properties of quinine. In the experimental part, the properties of quinine solutions containing different electrolytes were analysed by UV-VIS spectrophotometer and fluorescence spectroscopy. Two different types of configurations of plasma discharges in liquids were used. Solutions were compared on the base of different concentration of quinine, different electrolytes, different configurations of plasma discharges and pH values of the solutions. Furthermore, the experimental work focuses on quinine solutions with the sodium nitrate. The time instability of the solutions was analysed. Also, the influence of the solution age and different types of the plasma discharge on the excitation and emission spectra of quinine were investigated.
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Study of plasma effects on quinine solutions
Procházková, Michaela ; Dzik, Petr (referee) ; Kozáková, Zdenka (advisor)
This diploma thesis focuses on quinine solutions and quality of these solutions after applying plasma discharge. These electric discharges can be used to destroy some substances from the water. The theoretical part is focused on description of electric discharges in liquids and on the properties of quinine. In the experimental part, the properties of quinine solutions containing different electrolytes were analysed by UV-VIS spectrophotometer and fluorescence spectroscopy. Two different types of configurations of plasma discharges in liquids were used. Solutions were compared on the base of different concentration of quinine, different electrolytes, different configurations of plasma discharges and pH values of the solutions. Furthermore, the experimental work focuses on quinine solutions with the sodium nitrate. The time instability of the solutions was analysed. Also, the influence of the solution age and different types of the plasma discharge on the excitation and emission spectra of quinine were investigated.
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Comparison of Calibration Methods for Determination of Quinine in Beverages
Handlová, Zuzana ; Nesměrák, Karel (advisor) ; Kozlík, Petr (referee)
The aim of this bachelor thesis is to compare three calibration methods used for determination of quinine in beverages performed by two instrumental methods. As the calibration methods, calibration curve method, standard addition method and spike were chosen. As the instrumental methods, UV spectrometry and RP-HPLC with UV and fluorescence detection were chosen. The calibration methods were compared in terms of accuracy, precision, and time consumption. The instrumental methods were compared in terms of accuracy. Five different tonic waters were chosen as authentic samples. The most precise results were provided by the calibration curve method. In terms of accuracy it was not possible to determine the most accurate calibration method. Spike was the least time-consuming calibration method. HPLC was more accurate compared to spectrometry. Key words: analytical calibration, spectrometry, high performance liquid chromatography, quinine
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Chemical aposematism: reactions of predators towards chemical warning signals of prey
Chalušová, Kateřina ; Exnerová, Alice (advisor) ; Kotyková Varadínová, Zuzana (referee)
An aposematism is a type of defence mechanism, by which a prey demonstrates towards predator that it is unpalatable and toxic. The reactions of predators towards chemical warning signals of prey differ due to the quantity and a combination of signals showed by prey, the predator species and its primary orientation. Most of works tested reactions of birds towards gustatory and olfactory stimuli, often in combination with signals from other modalities. Although the birds are predators which orientate primarily visually, olfaction, gustation and chemesthesis significantly helped them with determining unpalatable food. Among other tested predators were fish, amphibians, reptiles, mammals and invertebrates and their reactions towards the same chemicals of prey are noted for comparison. The main chemicals used in the experiments regarding birds were denatonium benzoate (Bitrex), quinin and pyrazines. Predators often showed an aversive behaviour, neophobic reactions, accelerated learning and more effective memorizing of the unpalatable prey if it was presented together with chemical signals. Some of the predators were able to control their toxin intake relative to the amount of toxin ingested or to discriminate between palatable and unpalatable food according to the chemical concentration in it. Key...
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Study of electrochemical behaviour of quinine and cinchonidine at boron doped diamond electrode
Brunovská, Veronika ; Schwarzová, Karolina (advisor) ; Nesměrák, Karel (referee)
In this thesis, it was for the first time studied the electrochemical behaviour of cinchona alkaloids quinine and cinchonidine by cyclic voltammetry and differential pulse voltammetry using boron doped diamond (BDD) thin film as an electrode material. Cyclic voltammograms did not exhibit any significant anodic signals corresponding to a simple electrode reaction. However, current increase with indistinctive maxima compared to the basic electrolyte was recorded in Britton - Robinson buffers with pH 2,0 − 12,0 medium. Accordingly, insignificant signals observable in the cathodic area at far negative potential close to the potential of decomposition of the supporting electrolyte , presumably to the reduction of quinoline skeleton. It was found by means of differential pulse voltammetry that the number of those observable current maxima varies for quinine and cinchonidine in different supporting electrolytes. Quinine provided the best developed anodic peaks in the medium of BR buffer pH 5,0 and 6,0 and cinchonidine in pH 7,0, 9,0 and 12,0. The calibration dependence of anodic peak of quinine in BR buffer pH 5,0 is linear in the concentration range 6∙10−6 mol∙l−1 − 1∙10−4 mol∙l−1 with limit of quantitation 4,39∙10−6 mol∙l−1 . In the cathodic area the limit of quantitation is 4,33∙10−5 mol∙l-1 . The...
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