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Modular design for in-atomizer preconcentration of hydride forming elements with AAS detection
Novák, Petr ; Kratzer, Jan (advisor) ; Korunová, Vlasta (referee)
Modular design of hydride trap-and-atomizer device for AAS is constructed and tested. Modular design enables to test different preconcentration surfaces easily. Efficient in- atomizer preconcentration allows to reach detection limits of hydride forming elements at ultratrace levels. Bismuth and arsenic were chosen as model analytes and their preconcentration efficiencies were quantified employing quartz and sapphire as preconcentration surfaces. The results reached in the modular design were compared to those found previously in the compact quartz trap-and-atomizer device. The performance of the modular design is fully comparable with that of compact trap-and-atomizer design. Modular design can thus be employed for testing of novel preconcentration surfaces.
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A novel AAS atomizer based on a dielectric barrier plasma discharge
Novák, Petr ; Kratzer, Jan (advisor) ; Kanický, Viktor (referee)
Atomization of arsine in a novel hydride atomizer for atomic absorption spectrometry (HG-AAS) was thoroughly optimized. This plasma atomizer is based on a dielectric barrier discharge (DBD). Sensitivity and detection limit reached 0.48 s ng-1 As and 0.16 ng ml-1 As, respectively, under optimum atomization conditions (Ar discharge using a flow rate of 60 ml min-1 Ar, DBD power 17 W). Analytical figures of merit reached in DBD are comparable to those found in an externally heated quartz tube multiatomizer (MMQTA) that was chosen as a model of conventional approach to hydride atomization in HG-AAS. An extent of interferences (Se, Sb, Bi) during As determination was investigated comparing both MMQTA and DBD atomizers. The later one was found to be more resistant towards interferences. A simple preconcentration of As in a DBD atomizer was reached after oxygen introduction into the Ar plasma in the DBD resulting in analyte retention in the atomizer followed by its volatilization once the oxygen flow is switched off. Preconcentration efficiency of 100 % was reached and detection limit improvement by a factor of ten was achieved (0.01 ng ml-1 As, preconcentration period 300 s).
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HG-AAS with atomization in a dielectric barrier plasma discharge: method optimization and analytical applications
Zurynková, Pavla ; Kratzer, Jan (advisor) ; Kanický, Viktor (referee)
The aim of this diploma thesis was to optimize in detail atomization conditions for antimony hydride in a novel plasma atomizer based on a dielectric barrier discharge (DBD) with atomic absorption spetrometric detection. Argon was found as the best DBD discharge gas employing a flow rate of 50 ml min-1 Ar while the DBD power was optimized at 30 W. Analytical figures of merit including interference study of As, Se and Bi have been subsequently investigated and the results compared to those found in an externally heated quartz tube atomizer (QTA). The limit of detection reached in DBD (0.15 ng ml-1 Sb) is comparable to that observed in QTA (0.14 ng ml-1 Sb). Finally, possibility of stibane preconcentration in a DBD atomizer was studied. Preconcentration efficiency of 102 ± 6 % was found under optimized conditions.
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HG-AAS with atomization in a dielectric barrier plasma discharge: method optimization and analytical applications
Zurynková, Pavla ; Kratzer, Jan (advisor) ; Kanický, Viktor (referee)
The aim of this diploma thesis was to optimize in detail atomization conditions for antimony hydride in a novel plasma atomizer based on a dielectric barrier discharge (DBD) with atomic absorption spetrometric detection. Argon was found as the best DBD discharge gas employing a flow rate of 50 ml min-1 Ar while the DBD power was optimized at 30 W. Analytical figures of merit including interference study of As, Se and Bi have been subsequently investigated and the results compared to those found in an externally heated quartz tube atomizer (QTA). The limit of detection reached in DBD (0.15 ng ml-1 Sb) is comparable to that observed in QTA (0.14 ng ml-1 Sb). Finally, possibility of stibane preconcentration in a DBD atomizer was studied. Preconcentration efficiency of 102 ± 6 % was found under optimized conditions.
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Selenium determination by HG-AAS with preconcentration and atomization in a dielectric barrier plasma discharge
Duben, Ondřej ; Kratzer, Jan (advisor) ; Rychlovský, Petr (referee)
The aim of this thesis was to optimize atomization conditions for selenium hydride in a novel plasma atomizer based on dielectric barrier discharge (DBD) using atomic absorption spectrometry as a detector. Analytical characteristics have been subsequently determined and compared to those reached in a conventional externally heated quartz tube atomizer which was replaced by a sofisticated design of a multiatomizer (MMQTA) in this work. The limit of detection reached in DBD (0,24 ng ml−1 Se) is slightly worse to that observed in MMQTA (0,15 ng ml−1 Se). On the contrary, slightly better resistance towards interferences of Sb, Bi and As was observed in DBD atomizer in comparison with MMQTA. Possibility of selenium preconcentration in a DBD atomizer was studied reaching an overall preconcentration efficiency of 75 ± 5%. The detection limit in a preconcentration mode employing preconcentration period of 300 s has reached 0,012 ng ml−1 Se. Key words: hydride generation atomic absorption spectrometry, dielectric barrier discharge, hydride atomization, hydride trapping, selenium
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A novel AAS atomizer based on a dielectric barrier plasma discharge
Novák, Petr ; Kratzer, Jan (advisor) ; Kanický, Viktor (referee)
Atomization of arsine in a novel hydride atomizer for atomic absorption spectrometry (HG-AAS) was thoroughly optimized. This plasma atomizer is based on a dielectric barrier discharge (DBD). Sensitivity and detection limit reached 0.48 s ng-1 As and 0.16 ng ml-1 As, respectively, under optimum atomization conditions (Ar discharge using a flow rate of 60 ml min-1 Ar, DBD power 17 W). Analytical figures of merit reached in DBD are comparable to those found in an externally heated quartz tube multiatomizer (MMQTA) that was chosen as a model of conventional approach to hydride atomization in HG-AAS. An extent of interferences (Se, Sb, Bi) during As determination was investigated comparing both MMQTA and DBD atomizers. The later one was found to be more resistant towards interferences. A simple preconcentration of As in a DBD atomizer was reached after oxygen introduction into the Ar plasma in the DBD resulting in analyte retention in the atomizer followed by its volatilization once the oxygen flow is switched off. Preconcentration efficiency of 100 % was reached and detection limit improvement by a factor of ten was achieved (0.01 ng ml-1 As, preconcentration period 300 s).
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Modular design for in-atomizer preconcentration of hydride forming elements with AAS detection
Novák, Petr ; Kratzer, Jan (advisor) ; Korunová, Vlasta (referee)
Modular design of hydride trap-and-atomizer device for AAS is constructed and tested. Modular design enables to test different preconcentration surfaces easily. Efficient in- atomizer preconcentration allows to reach detection limits of hydride forming elements at ultratrace levels. Bismuth and arsenic were chosen as model analytes and their preconcentration efficiencies were quantified employing quartz and sapphire as preconcentration surfaces. The results reached in the modular design were compared to those found previously in the compact quartz trap-and-atomizer device. The performance of the modular design is fully comparable with that of compact trap-and-atomizer design. Modular design can thus be employed for testing of novel preconcentration surfaces.
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