National Repository of Grey Literature 711 records found  1 - 10nextend  jump to record: Search took 0.09 seconds. 

Voltametrické stanovení sloučenin dusíku pomocí stříbrné pevné amalgámové elektrody
Daňhel, A. ; Barek, J. ; Josypčuk, Bohdan ; Pecková, K.
Silver amalgam is a good electrode material for construction of new types of electrodes. In this work a silver solid amalgam paste electrode was prepared. The pastes were mixed from a silver solid amalgam powder and a mineral oil, silicone oil, paraffin oil and tricresylphosphate, stuffed into a Teflon body of electrode. The silver paste amalgam electrodes are expected to provide new possibilities for determinations of electrochemically reducible compounds by modern voltammetric methods. The main expected advantage is the possibility of easily renewable surface as in the case of carbon paste electrodes.

The use of composite graphite electrode for voltammetric determination of phenylglyoxylic acid
Šenholdová, Z. ; Navrátil, Tomáš ; Shanmugam, K. ; Barek, J. ; Žák, J.
A composite electrode prepared from graphite powder and epoxy resin was applied as a working electrode for the determination of phenylglyoxylic acid (one of the metabolites of styrene) in human urine. Cathodic differential pulse stripping voltammetry was used and optimum conditions have been found giving the limit of determination about 5 mg L-1. All results were compared with those obtained using hanging mercury drop electrode. For the confirmation of suggested mechanism of the electrochemical reaction the elimination voltammetry with linear scan was used.

Voltammetric determination of genotoxic compounds using solid amalgam electrodes
Barek, J. ; Čížek, K. ; Fischer, J. ; Navrátil, Tomáš ; Josypčuk, Bohdan
Possibilities of voltammetric determinations of genotoxic organic compounds for environmental purposes were studied. Traditional mercury electrode was replaced by solid amalgam electrodes. It is possible to conclude that the obtained results are comparable with those, obtained on other types of electrodes.


Evaluation of ecotoxicity of selected chemicals with using algal test.
Kosárová, Hedvika ; Pavlovský, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
This bachelor thesis deals with the ecotoxicity of 2 - [(2,6-dichlorophenyl)aniline] benzene acetic acid (diclofenac), ?-methyl-4-(2-methylpropyl) benzene acetic acid (ibuprofen) and mixture of cadmium and diclofenac and studies the above using algal toxicity test in accordance with ISO 8692. The theoretical part describes the issue of pharmaceuticals in the environment, and characteristics of standards algae tests and alternative tests. Freshwater green algae Desmodesmus subspicatus were used as testing organisms in all the implemented algal toxicity tests. By the means of these tests, the IrC50 values for the standard substance potassium dichromate, the drugs diclofenac and ibuprofen and cadmium were determined. The toxicity of cadmium in mixture with diclofenac was also evaluated.

Residuals of pharmaceuticals in waters
Vašíčková, Petra ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
This bachelor thesis focuses on studying synthetic pharmaceuticals spreading into the aquatic ecosystem. Ketoprofen and diclofenac, non-steroidal analgetics were studied. The aim of this work is to develop both a suitable analytic method for analytes isolation from a given matrix and an optimal technique for identification and determination of analgetics residues in waters. Solid phase extraction (SPE) was employed as the separation method for isolation of given pharmaceuticals and high performance liquid chromatography (HPLC) with diode-array detection was used for their determination. The optimised and validation method was used to model samples of water. Obtained results were evaluated and their interpretation was done.

Artificial sweeteners and their potential impact on the ecosystem
Vavrčíková, Veronika ; Mravcová, Ludmila (referee) ; Zlámalová Gargošová, Helena (advisor)
This diploma thesis deals with the determination and ecotoxicological assessment of artificial sweeteners. The diploma was focused on monitoring the most commonly used sweeteners, which includes acesulfam-K, cyclamate, saccharin and sucralose. These sweeteners were analyzed by liquid chromatography with mass spectrometry, using solid phase extraction for their concentration. The samples for their determination were taken from wastewater treatment plant in Modrice. Artificial sweeteners are synthetically produced substances, which is the main reason for their occurrence in waste water. Some of them are not efficiently removed from the wastewater treatment plant and penetrate into the environment. Analysis of the samples was found, that sucralose penetrates into the environment. The ecotoxicological effect of the sweeteners was evaluated via aquatic organisms, namely on the freshwater crustaceans Thamnocephalus platyurus and Daphnia magna, on the water plant Lemna minor, and the battery of tests was supplemented by a representative of the destructors Vibrio fischeri. For all sweeteners, LC20, EC20 and IC20 values were determined. For some sweeteners, LC50, EC50 and IC50 values were also determined. During testing, saccharin represented the highest toxicity.


Voltammetric Determination of one of Styrene Metabolites - Phenylglyoxylic Acid - in Urine Using Graphite Composite Electrode
Navrátil, Tomáš ; Shanmugam, K. ; Šenholdová, Z. ; Heyrovský, Michael ; Surovcová, H.
Phenylglyoxylic acid is metabolized in human body from vinylbenzene (styrene) (from which polystyrene is produced). Presented work deals with determination of this metabolite in human urine using carbon composite electrode.

Valuation of the company DEKTRADE, a.s.
Krupa, Štěpán ; Scholleová, Hana (advisor) ; Habrnal, Marek (referee)
The aim of this Master's Thesis is valuation of the company DEKTRADE, a.s. as determined by possible independent analytic using publicly accessible information or data that could be acquired when in touch with management of the company as at January 1st 2013. Results of the thesis are supposed to analyze the corporation itself from the strategically-financial point of view, specify the height of its value if offered to a potential buyer and at last but not at least to help the board of managers to see the conceivable outlook of main competitors on DEKTRADE, a.s. The Thesis is split to theoretical and practical part where the first one should constitute solid methodological base for the final valuation of the company. Keystones of the latter are strategic and financial analysis followed by financial plan and specific techniques of valuation of the company. The ending of the Thesis is devoted to Monte Carlo simulation of results with respect to risk exposition of the computed values.