Determination Of Lead By Flame Atomic Absorption Spectrometer Improved With Branched Capillary As Hydride Generator

The sensitivity of traditional flame atomic absorption spectrometry (FAAS) is low for the determination of lead. Therefore, hydride generation and double capillary sampling techniques were used in this study. Using a Y-shaped connector, the sampling capillary of a traditional FAAS instrument equipped with Zeeman background correction was branched, with one for introducing the reductant solution, KBH4, and the other for sample solution, Pb4+. The KBH4 solution and the Pb4+ solution were then merged and mixed inside the reaction capillary and thereafter inside the nebulizer for generating the lead hydride, which, together with the liquid fine droplets, was directly brought into the air-acetylene flame for atomization without gas/liquid separation. Then the lead atomic absorption signal was determined at 283.3 nm.The experimental conditions were optimized for best signal-to-noise ratio (S/N). It was found that sample acidity, the concentration of KBH4 and the concentration of KOH (as a stabilizing agent for KBH4) were important variables affecting lead hydride generation, and the three factors interacted with each other. Hence, an orthogonal design was used for the optimization of all these three factors. The concentration of K3Fe(CN)6 and the length of reaction capillary also affected the...