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Photochemical generation of volatile species of rhodium as an efficient sample introduction technique for inductively coupled plasma mass spectrometry
Hašlová, Karolína ; Musil, Stanislav (advisor) ; Nováková, Eliška (referee)
This master's thesis is focused on development of a new analytical method based on photochemical generation of volatile species (PCVG) of rhodium as an efficient sample introduction technique for inductively coupled plasma mass spectrometry. At first, the conditions affecting the PCVG efficiency were optimized, namely carrier gas flow rate, irradiation time, composition of the reaction medium as well as the impact of transition metal ions as potential sensitizers was examined. The combination of Cu2+ and Co2+ was found optimal, enhancing the PCVG efficiency more than 60-fold. Additionally, a serious effect of the residence time of volatile species in the reaction medium, after exiting the irradiated part of the photoreactor, was found. The PCVG efficiency was doubled by modifying the output part of the photoreactor and another two-fold increase in the PCVG efficiency was achieved using the addition of nitrate anions to the reaction medium. Under chosen optimal conditions, the limit of detection and quantification were 13 pg dm-3 (3σ, n = 11) and 42 pg dm-3 (10σ, n = 11), respectively, and the PCVG efficiency was determined to be 13.5 ± 0.1%. The repeatability (n = 10) at 20 ng dm-3 was 2.9%. These experiments were followed by a study of interferences commonly occurring in the PCVG methods (chloride...
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Photochemical generation of volatile species of nickel for analytical atomic spectrometry methods
Šoukal, Jakub ; Musil, Stanislav (advisor) ; Kratzer, Jan (referee)
This thesis deals with optimization of conditions of photochemical generation of volatile species of nickel for atomic absorption spectrometry. The volatile species of nickel were generated in the flow arrangement, when sample was injected to a stream of a reaction medium. Either formic acid was used as the reaction medium or formic acid with the addition of formate anions. Two types of a generator were tested, a generator with a PTFE tube wrapped around a mercury UV lamp and a high efficiency generator with an inside channel. At the same time, two types of a gas-liquid separator were tested. Diffusion flame was used as an atomizer due to its high robustness. Quartz atomizer didn't provide higher sensitivity and measurements had worse repeatability. All the parameters affecting atomization in the diffusion flame were optimized (flow rates and composition of gases, observation height). In the next section, conditions of generation (irradiation time, HCOOH concentration, addition of formate anions) were optimized. Interferences of inorganic acids in photochemical generation were investigated as well. It was found out that the generator with the inside channel provided slightly higher sensitivity and thus generation efficiency than the generator with the PTFE tube wrapped around. Transmission of...
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