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Atomization of hydride forming elements in dielectric barrier plasma discharges
Baranová, Barbora
The aim of this diploma thesis was to optimize the atomization conditions of two hydride forming elements - bismuth and tellurium in dielectric barrier discharge (DBD) plasma atomizers using atomic absorption spectrometry (AAS) as a detector. Two types of electrode constructions of planar DBD atomizers were studied: glued and sputtered electrodes while two construction of high voltage power supply sources were investigated employing either a sinusoidal or square wave modulation of high voltage function. The effect of the gas phase dryer included in the apparatus upstream the atomizer was also investigated. A nafion membrane tube dryer was identified as the most effective one. Its efficiency was verified using optical emission spectrometry. With the nafion tube included in the apparatus, two main parameters of DBD atomizers were optimized: the voltage of the power supply source and argon flow rate, which served as a discharge gas. Using optimal conditions, analytical characteristics were determined for all atomizers used and these were subsequently compared with those achieved in an externally heated quartz (multi)atomizer (MM)QTA. In the case of bismuth, the optimal argon flow rate was determined to be 75 cm3 min-1 for all atomizers. The optimal value for the power supply source with sinusoidal...
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Atomization of hydride forming elements in dielectric barrier plasma discharges
Baranová, Barbora ; Kratzer, Jan (advisor) ; Hrdlička, Aleš (referee)
The aim of this diploma thesis was to optimize the atomization conditions of two hydride forming elements - bismuth and tellurium in dielectric barrier discharge (DBD) plasma atomizers using atomic absorption spectrometry (AAS) as a detector. Two types of electrode constructions of planar DBD atomizers were studied: glued and sputtered electrodes while two construction of high voltage power supply sources were investigated employing either a sinusoidal or square wave modulation of high voltage function. The effect of the gas phase dryer included in the apparatus upstream the atomizer was also investigated. A nafion membrane tube dryer was identified as the most effective one. Its efficiency was verified using optical emission spectrometry. With the nafion tube included in the apparatus, two main parameters of DBD atomizers were optimized: the voltage of the power supply source and argon flow rate, which served as a discharge gas. Using optimal conditions, analytical characteristics were determined for all atomizers used and these were subsequently compared with those achieved in an externally heated quartz (multi)atomizer (MM)QTA. In the case of bismuth, the optimal argon flow rate was determined to be 75 cm3 min-1 for all atomizers. The optimal value for the power supply source with sinusoidal...
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Next generation of hydride atomizers based on dielectric barrier plasma discharge
Kráľová, Zuzana ; Kratzer, Jan (advisor) ; Hrdlička, Aleš (referee)
Atomization conditions for selenium and lead hydrides in a dielectric barrier discharge (DBD) plasma atomizer with detection by atomic absorption spectrometry (AAS) were investigated in this work. Two designs of DBD atomizers were studied, the first one with glued electrodes and the second one with sputtered electrodes. The main experimental parameters were optimized, including supplied power and discharge gas (argon) flow rate. Additionally, the effect of several dryers was studied. Analytical figures of merit were determined for both plasma atomizers under the optimized conditions and compared to multiatomizer (MMQTA) as the most common hydride atomizer. The optimum flow rate for selenium determination was 75 cm3 min-1 Ar for both DBD atomizer designs as well as for MMQTA. In case of lead hydride atomization, ideal flow rate of argon was 175 cm3 min-1 for DBD atomizer with glued electrodes and 150 cm3 min-1 with DBD atomizer with sputtered electrodes, while MMQTA required only 100 cm3 min-1 Ar. The optimal power supply for DBD with sputtered electrodes was found significantly lower at 7.3 W for selenium and 13.3 W for lead. A dryer based on nafion membrane was found as the most effective for both analytes studied. Its efficacy was verified by optical emission spectrometry. As for analytical...
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