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Comparision of methods for sulphide determination
Zlámalová, Magda ; Červený, Václav (referee) ; Nesměrák, Karel (advisor)
The aim of this work is determination of sulphides in a solution by suitable methods and it's subsequent comparison from a point of view to the precision, financial and time demands. Iodometric titration, argentometric titration, and potassium ferricyanide titration were chosen for the determination of sulphides in the solution. Anhydrous sodium sulphide and sodium sulphide hydrate were used as model samples. From the point of view to financial and time demands the most advantageous method was potassium ferricyanide titration and the least advantageous method was iodometric titration. The precision of used methods was dependent on type of used sample. Iodometry was the least precise determination of sulphides in the sample of anhydrous sodium sulphide; the precision of argentometry and potassium ferricyanide titration was comparable. Potassium ferricyanide titration was the most precise determination of sulphides in the sample of sodium sulfide hydrate; the least precise determination was argentometry.
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Increasing of the efficiency of electrochemical generation of volatile form of cadmium for trace analysis using AAS
Růžková, Pavla ; Rychlovský, Petr (advisor) ; Červený, Václav (referee)
The aim of the diploma thesis was an improvement of the efficiency of electrochemical generation of volatile form of cadmium used in atomic spectrometric methods. The increase of the efficiency of electrochemical generation of volatile form results in overall improvement of the sensitivity of measurement and therefore, it is possible to achieve lower values of detection limits and limits of determination. One of all the possibilities for improving of overall efficiency is a minimization of loss of volatile form of Cd during transport. Another essential possibility is coupling of the technique of electrochemical generation of volatile form of Cd with in-situ collection (and atomization) in graphite furnace of atomic absorption spectrometer. Keywords: Atomic absorption spectrometry, electrochemical generation of volatile compounds, generation efficiency, electrolytic flow-through generation cell, quartz-tube atomizer, graphite furnace, in-situ trapping, cadmium
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Novel Approaches to the Application of Electrochemical Volatile Compounds Generation in Spectrometric Methods
Červený, Václav ; Rychlovský, Petr (advisor) ; Spěváčková, Věra (referee) ; Komárek, Josef (referee)
Various possibilities for the use of electrochemical generation of volatile compounds for the determination of trace and ultratrace quantities of elements using atomic absorption spectrometry and optical emission spectrometry, respectively, were studied in this work. The Thesis is divided into four thematic sections. Electrochemical cold mercury vapor generation is common to the first two parts. The third part is devoted to electrochemical generation of the volatile form of cadmium and the last part deals with the use of the electrochemical hydride generator as a derivatization unit for speciation analysis of arsenic compounds. The optimization of each individual determination was carried out including, for example, various designs of the generator of volatile compounds (forms) of the analyte, the changes in the design of the gas-liquid separator, optimization of the concentration and the flow rate of all the solutions and the carrier gas. However, the value of the electric current employed was the most important parameter. In the first section, the in-situ trapping system of the cold mercury vapor generated in the graphite furnace (with the inner surface covered with a gold foil) of the atomic absorption spectrometer was also designed and optimized. The absolute limit of detection, 80 pg, was...
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Public Key Infrastructure audit approaches
Pěnka, Michal ; Doucek, Petr (advisor) ; Červený, Vlastimil (referee)
The aim of this work is to introduce fundamental concepts of public key infrastructure. Basic requirements for communication and related problems are presented. The solution of these problems can be found in cryptography. Different types of cyphers and infrastructures based on assymetric cryptography are described. The infrastructure types involve hierarchical system of certificate authorities and the web of trust. Furthermore, there is a list and description of cryptography software which can be used in the field of public key infrastructre. The main topic of this thesis is the audit of public key infrastructure. Audit can be supported by several available standards, e.g. WebTrust for Certificate Authorities, ETSI TS 101 456, ETSI TS 102 042 and ISO 21188:2006. This paper systematically describes these standards and using statistical methods compares and evaluates their complexity.
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