Hydride generation atomic absorption spectrometry with a dielectric barrier discharge atomizer: Method optimization and evaluation of analytical performance for tin

Abstract

Atomization conditions for tin hydride in the planar dielectric barrier discharge (DBD) plasma atomizer were optimized with detection by atomic absorption spectrometry (AAS). The effects of apparatus arrangement such as the shape of a waveform function of the high voltage power supply source, DBD atomizer design as well as presence of a dryer tube filled with NaOH pellets to prevent residual aerosol and moisture transport into the DBD were investigated in detail. The optimal experimental setup consisted of a square wave high voltage power supply source coupled to a DBD with vapor-deposited electrodes in the presence of NaOH dryer upstream the DBD atomizer. Argon was found as the best discharge gas under a flow rate of 120 mL min−1 while the DBD optimum high voltage supply rate was 7 kV. A sensitivity of 0.05 s ng−1 Sn and a limit of detection of 1.1 ng mL−1 Sn were reached under optimized conditions. Optimization of the whole experimental setup resulted in 7-fold improvement of sensitivity compared to the original arrangement consisting of a sinusoidal source coupled to a DBD atomizer with glued electrodes in absence of the dryer. The analytical performance of the DBD atomizer under optimized conditions was compared to that of a commonly used externally heated quartz tube atomizer.