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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 vapor generation of rhenium with a detection by inductively coupled plasma mass spectrometry
Hašlová, Karolína ; Musil, Stanislav (advisor) ; Nováková, Eliška (referee)
This bachelor thesis deals with an optimization of the conditions of photochemical vapor generation of rhenium with detection by inductively coupled plasma mass spectrometry. Photochemical vapor generation was realized using an ultraviolet irradiation in a high-efficiency photochemical reactor with an inner reaction channel from a formic acid based medium in presence of reaction modifiers. Optimizations of parameters affecting the generation efficiency was implemented step by step - reaction medium flow rate (irradiation time), formic acid concentration, addition of acetic acid and reaction modifiers (transition metals) and carrier gas flow rate. The addition of an appropriate combination of reaction modifiers - cadmium(II) and iron(II) ions, had a key impact on photochemical generation of volatile species of Re and led to more than 40-fold increase in generation efficiency. A further (2-fold) increase in generation efficiency was achieved by wrapping the high-efficiency photochemical reactor with an aluminum foil, probably due to more efficient irradiation of the sample in the generator. The limit of detection and quantification were determined as 0.24 ng dm-3 and 0.80 ng dm-3 Re, respectively. The repeatability of the method 100 ng dm-3 Re was 4.8%. Key words photochemical vapor generation,...
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