Atomization of lead hydride in a dielectric barrier discharge atomizer: Optimized for atomic absorption spectrometry and studied by laser-induced fluorescence

Abstract

Atomization of lead hydride in a plane-parallel volume dielectric barrier discharge (DBD) atomizer coupled to a high voltage power supply source with sinusoidal waveform (28.5 kHz) was optimized with detection by atomic absorption spectrometry. Argon was found as the best discharge gas under a flow rate of 175 mL min−1 while the DBD optimum peak-to-peak high voltage was 25 kV. The performance of the novel DBD atomizer was compared to that of a conventional externally heated quartz tube atomizer (QTA) operating at 900 °C and 100 mL min−1 Ar carrier gas flow rate. Sensitivity and limit of detection (LOD) in QTA reached 0.21 s ng−1 Pb and 0.6 ng mL−1 Pb, respectively, while they reached 0.04 s ng−1 Pb and 2.3 ng mL−1 Pb in DBD. Laser-induced fluorescence (LIF) was employed to investigate the spatial distribution of free Pb atoms as well as to quantify lead hydride atomization efficiency in both atomizers. Free Pb atoms were present only in a central region of DBD atomizer. Atomization efficiency of lead hydride was quantified by LIF to be 23 ± 7%. On the contrary, free Pb atoms were distributed homogeneously along the whole optical arm in the QTA with atomization efficiency reaching 88 ± 18%.