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New Methods of Oxygen Removal from Analyzed Solutions in Voltammetric Determination of Organic Compounds
Batěk, Jan ; Vyskočil, Vlastimil (advisor) ; Schwarzová, Karolina (referee)
The aim of this Bachelor Thesis was to verify new methods of oxygen removal from analyzed solutions in voltammetric determination of organic compounds. A method of chemical reduction was chosen to remove dissolved oxygen. Carbohydrazide, N,N-diethylhydroxylamine and 2-butanone oxime were used for removal of dissolved oxygen. These substances are used to remove oxygen from boiler systems. The last agent used to remove oxygen was sodium sulfite. Differential pulse voltammetry (DPV) was used to monitored the ability of oxygen scavengers. The effect of pH of the solution (Britton-Robinson buffer) on oxygen removal was also investigated. A solution of 4-nitrophenol at a concentration of 1∙10−4 mol∙l−1 was used as a model substance in these assays. We have found that carbohydrazide had no effect to remove oxygen in the whole pH range. Using sodium sulphite, oxygen was removed from the analyzed solution at pH 8, 10 and 12. Determination of 4-nitrophenol was thus possible. Using N,N-diethylhydroxylamine at pH 10 and 12 and 2-butanone oxime at pH 8, 10 and 12, oxygen was removed from the analyzed solutions. However, these substances are unsuitable for the determination of 4-nitrophenol.
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Usage of chemical weapons during the First World War and an edification for the present
PRAŽÁK, Marek
This thesis focuses on the description and characteristics of chemical weapons used during the First World War (WWI) and the consequences resulting from it to the present. The introductory part tries to present a comprehensive description of chemical weapons, their classification, including a basic description of their effects on the human organism. Further on, the thesis characterizes individual chemical substances used in the battles of the WWI between 1914 and 1918 and it mentions the most important and key attacks with warfare chemical substances, including a description of the development and design of chemical ammunition used. The next section of the thesis is devoted to the protection against weapons of mass destruction and, in particular, various types of protection and I assess the impact of the use of chemical weapons during the First World War to the present time. Regarding the methodology side, I gathered information from specialized sources and tried to map out clearly and in general the given issues, also based on my own knowledge and experience. The thesis is based on two basic hypotheses: 1 The First World War showed that if necessary the warring parties would resort also to the use of banned means, including chemical weapons; 2. The First World War laid the building blocks of modern protection against chemical weapons and the protection against weapons of mass destruction in general. Both of the hypotheses have been proven to be true, which I try to document in my thesis. The first hypothesis shows that even if chemical weapons were officially banned at The Hague conference, the warring parties did not hesitate, if necessary, to produce, improve and use them against their enemies. The second hypothesis is confirmed by the fact that along with the development and improvement of chemical weapons and ammunition the protection against these weapons developed and improved as well as the detection of warfare chemical substances and alerting of troops when such weapons are used. The consequence of this is the existence of current chemical protection and the emergence of a new military branch - Protection against the Weapons of Mass Destruction.
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