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The effect of selected compounds on determination of antimony by atomic fluorescence spectrometry with UV-photochemical generation of volatile compounds
Jelínková, Klára ; Červený, Václav (advisor) ; Nováková, Eliška (referee)
5 Abstract This bachelor thesis is focused on the investigation of the influence of selected chemical individuals on the determination of antimony by UV-photochemical generation of volatile compounds with atomic fluorescence spectrometry detection (UV-PVG-AFS). Antimony, as a toxic semimetal occurring mainly in the trivalent and pentavalent oxidation state, plays an important role in many industries. Its determination is of importance not only from the point of view of analytical chemistry but also for monitoring of its environmental effects and for human health. For the interference studies with Sb5+ , the inorganic ions Br− , Cr2O7 2− , I− , CO3 2− , K+ , Cr3+ , Cd2+ , Co2+ , Cu2+ , Ni2+ , Na+ , Zn2+ , the organic solvents acetonitrile, ethanol and methanol, as well as the extraction reagents L-cysteine and 2-mercaptoethanol were chosen. Br− , Cr2O7 2− , I− , CO3 2− , K+ , Cr3+ , Cd2+ , Na+ and Zn2+ were chosen as possible interferents in the determination of Sb3+ . Solutions of the interferents were prepared in a medium of acetic acid (35%v/v) and 50 g l−1 Sb3+ or Sb5+ . The detection limit of the determination of Sb3+ in the flow injection mode analysis was 3.7 g l−1 for peak area and 1.9 g l−1 for peak height evaluation. For Sb5+ determination, the detection limit was 3.6 g l−1 for peak area and...
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Study of properties of UV-photochemical generation of volatile compounds od antimony
Adámková, Dominika ; Červený, Václav (advisor) ; Hraníček, Jakub (referee)
The master thesis deals with comparison of atomic fluorescence spektrometry and high resolution continuum source atomic absorption spektrometry for three methods generation of volatile compounds Antimony. In both methods of atomic antimony detection, it compares the most common chemical generation of volatile compounds (hydrides) with two alternative methods - electrochemical and UV - photochemical. The values of performance parameters for the determination of Sb(III) and Sb(V) were determined for all the above combinations. In the case of chemical generation, a surprisingly almost four times higher limit of detection of Sb(III) was found in connection with AFS detection than AAS detection. The final part was devoted to UV - photochemical vapor generation, with AAS detection for Sb(III) reaching limit of detection 4,96 ppb, for Sb(V) 8,63 ppb. Although UV - photochemical generation of volatile antimony compounds did not reach such performance parameters as chemical or electrochemical generation, it was observed that the sensitivity of antimony determination increased greatly when introducing oxygen into the apparatus. The interference study also found a significant positive effect of Fe(II) on the generation efficiency, and this modification partially persisted without further introduction of these...
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Determination of Te(IV) by photochemical generation of volatile compounds with atomic spectrometric detection
Ruxová, Helena ; Hraníček, Jakub (advisor) ; Šíma, Jan (referee)
This thesis deals with the development of a method suitable for determination Te(IV) by UV-photochemical generation of volatile compounds (UV-PVG) in liquid samples. Atomic absorption spectrometry (AAS) and atomic fluorescent spectrometry (AFS) were used as detection methods. The basis of the apparatus for UV-PVG was a mercury lamp wrapped by PTFE capillary. Firstly, the experimental parameters were optimized for both methods. The optimized parameters were the type, concentration, pH and flow rate of the reaction medium, the length of the PTFE reaction coil, carrier gas flow rate (argon), supportive gas flow rate (hydrogen) and atomization temperature. The figures of merit with both detection methods were determined and compared after the method was optimized. Detection limits achieved for these two detection methods were 6,0 µg dm-3 for AFS and 1,50 µg dm-3 for AAS. Performed interference study confirmed a significant effect of many cations of transition metals and hydride forming elements on tellurium determination. The influence of nitric acid in the sample was studied separately. The suitability of the method for tellurium determination was confirmed by using a spiked certified reference material.
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Interferences in determination of antimony by UV-photochemical generation of volatile compounds and atomic fluorescence spectrometry
Kračmarová, Aneta ; Červený, Václav (advisor) ; Hraníček, Jakub (referee)
This work is focused on the study of interferents of selected elements during UV-photochemical generation of volatile antimony compounds. The interferents included transition metals, halides, hydride-forming elements and salts of mineral acids. Detection was performed by atomic fluorescence spectrometry. Some of the tested added substances proved to be potential reaction modifiers; in their presence, an increase in responses was observed. The best results were obtained using Fe3+ for the determination of Sb3+ and SO4 2- had the best results for the determination of Sb5+ . The largest interferent, i.e. the substance causing the most significant decrease in signal, was for both antimony ions Se4+ .
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Speciation analysis of arsenic and mercury using postcolumn generation of their volatile compounds for needs of atomic spectroscopic methods
Linhart, Ondřej
The presented dissertation thesis deals with the use of UV-photochemical generation of volatile compounds (UV-PVG) as a derivatization technique for the combination of high-performance liquid chromatography (HPLC) and atomic absorption spectrometry (AAS) detection. Two model elements arsenic and mercury and their compounds were selected for the speciation analysis. The work was divided into several parts that follow. In the first part of the research, the apparatus for the UV-photochemical generation of the volatile mercury compounds and their detection with a new continuum source and high-resolution atomic absorption spectrometer (HR-CS AAS) with an externally heated detection tube was constructed. The analytical method was adapted for use with atomic fluorescence detection with the aim to improve sensitivity of the determination. Furthermore, apparatus for the electrochemical generation of cold mercury vapor with AAS detection was built. The construction of the apparatus was followed by optimization of the reaction conditions (concentration and flow of electrochemical reagents: sulfuric and hydrochloric acid, mobile phase, carrier medium, flow rate of the carrier gas and localization of its introduction), determination of the analytical figures of merit, and comparation of the methods. Both...
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Study of properties of UV-photochemical generation of volatile compounds od antimony
Adámková, Dominika ; Červený, Václav (advisor) ; Hraníček, Jakub (referee)
The master thesis deals with comparison of atomic fluorescence spektrometry and high resolution continuum source atomic absorption spektrometry for three methods generation of volatile compounds Antimony. In both methods of atomic antimony detection, it compares the most common chemical generation of volatile compounds (hydrides) with two alternative methods - electrochemical and UV - photochemical. The values of performance parameters for the determination of Sb(III) and Sb(V) were determined for all the above combinations. In the case of chemical generation, a surprisingly almost four times higher limit of detection of Sb(III) was found in connection with AFS detection than AAS detection. The final part was devoted to UV - photochemical vapor generation, with AAS detection for Sb(III) reaching limit of detection 4,96 ppb, for Sb(V) 8,63 ppb. Although UV - photochemical generation of volatile antimony compounds did not reach such performance parameters as chemical or electrochemical generation, it was observed that the sensitivity of antimony determination increased greatly when introducing oxygen into the apparatus. The interference study also found a significant positive effect of Fe(II) on the generation efficiency, and this modification partially persisted without further introduction of these...
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Determination of Te(IV) by photochemical generation of volatile compounds with atomic spectrometric detection
Ruxová, Helena ; Hraníček, Jakub (advisor) ; Šíma, Jan (referee)
This thesis deals with the development of a method suitable for determination Te(IV) by UV-photochemical generation of volatile compounds (UV-PVG) in liquid samples. Atomic absorption spectrometry (AAS) and atomic fluorescent spectrometry (AFS) were used as detection methods. The basis of the apparatus for UV-PVG was a mercury lamp wrapped by PTFE capillary. Firstly, the experimental parameters were optimized for both methods. The optimized parameters were the type, concentration, pH and flow rate of the reaction medium, the length of the PTFE reaction coil, carrier gas flow rate (argon), supportive gas flow rate (hydrogen) and atomization temperature. The figures of merit with both detection methods were determined and compared after the method was optimized. Detection limits achieved for these two detection methods were 6,0 µg dm-3 for AFS and 1,50 µg dm-3 for AAS. Performed interference study confirmed a significant effect of many cations of transition metals and hydride forming elements on tellurium determination. The influence of nitric acid in the sample was studied separately. The suitability of the method for tellurium determination was confirmed by using a spiked certified reference material.
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Speciation analysis of arsenic and mercury using postcolumn generation of their volatile compounds for needs of atomic spectroscopic methods
Linhart, Ondřej
The presented dissertation thesis deals with the use of UV-photochemical generation of volatile compounds (UV-PVG) as a derivatization technique for the combination of high-performance liquid chromatography (HPLC) and atomic absorption spectrometry (AAS) detection. Two model elements arsenic and mercury and their compounds were selected for the speciation analysis. The work was divided into several parts that follow. In the first part of the research, the apparatus for the UV-photochemical generation of the volatile mercury compounds and their detection with a new continuum source and high-resolution atomic absorption spectrometer (HR-CS AAS) with an externally heated detection tube was constructed. The analytical method was adapted for use with atomic fluorescence detection with the aim to improve sensitivity of the determination. Furthermore, apparatus for the electrochemical generation of cold mercury vapor with AAS detection was built. The construction of the apparatus was followed by optimization of the reaction conditions (concentration and flow of electrochemical reagents: sulfuric and hydrochloric acid, mobile phase, carrier medium, flow rate of the carrier gas and localization of its introduction), determination of the analytical figures of merit, and comparation of the methods. Both...
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Speciation analysis of arsenic and mercury using postcolumn generation of their volatile compounds for needs of atomic spectroscopic methods
Linhart, Ondřej ; Červený, Václav (advisor) ; Spěváčková, Věra (referee) ; Šíma, Jan (referee)
The presented dissertation thesis deals with the use of UV-photochemical generation of volatile compounds (UV-PVG) as a derivatization technique for the combination of high-performance liquid chromatography (HPLC) and atomic absorption spectrometry (AAS) detection. Two model elements arsenic and mercury and their compounds were selected for the speciation analysis. The work was divided into several parts that follow. In the first part of the research, the apparatus for the UV-photochemical generation of the volatile mercury compounds and their detection with a new continuum source and high-resolution atomic absorption spectrometer (HR-CS AAS) with an externally heated detection tube was constructed. The analytical method was adapted for use with atomic fluorescence detection with the aim to improve sensitivity of the determination. Furthermore, apparatus for the electrochemical generation of cold mercury vapor with AAS detection was built. The construction of the apparatus was followed by optimization of the reaction conditions (concentration and flow of electrochemical reagents: sulfuric and hydrochloric acid, mobile phase, carrier medium, flow rate of the carrier gas and localization of its introduction), determination of the analytical figures of merit, and comparation of the methods. Both...
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Interference study by arsenic determination using UV-photochemical generation of its volatile species with AAS detection
Smolejová, Jana ; Červený, Václav (advisor) ; Nesměrák, Karel (referee)
This thesis deals with the interference study of the UV-photochemical generation of arsenic volatile species with AAS detection and it searches for a suitable reaction modifier, which would improve sensitivity of the As determination. Interferences were classified into 3 groups according to their influence on the As UV-photochemical volatile species generation. Ni2+ , Cu2+ , Cl− and merkaptoethanol belong among the negative interferents. HNO3, Fe3+ , ethanol, SO4 2− , TiO2 and L-cysteine belong among the low-level interferents. Co2+ , acetonitrile, triethanolamine, selenite and Bi3+ belong to a group, which increases the absorbance of arsenic and could, therefore, be called positive interferents. Concentration of 10 mg l−1 of Bi3+ significantly increases the level of absorbance of arsenic. This effect was utilized during measurement of calibration dependence and Bi3+ ions were used as the reaction modifier. The figures of merit of this method with reaction modifier were obtained. Limit of detection was 18 µg l−1 , limit of quantification was 60 µg l−1 , sensitivity was 1.144·10−3 l µg−1 , repeatability was 4.5 % (relative standard deviation) a linear range was 60 - 500 µg l−1 . We achieved eleven times better absorbance by using this reaction modifier compared to UV-photochemical volatile species...
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