Beginning of Atomization in Presence of Matrix Modifier in Graphite Furnace Atomic Absorption Spectrometry

Abstract

Lead, tin, indium or selenium forms an alloy of a palladium matrix modifier during its atomization process in a graphite furnace. This process was studied by measuring the effective (atomic) vapor temperature, showing that the atomization occurred in specific phases of the alloy. It was found that Pb is atomized in the phases Pd₃Pb₂-Pd₃Pb, Sn in the phases Pd₃Sn₂-Pd₂Sn-Pd₃Sn, In in the phases PdIn₃-Pd₂In₃-PdIn-Pd₂In, and Se in the phases Pd_mSn_n-Pd. In a Pb-Fe system having no solid solution at any concentration range, the temperature-rising curve was almost the same as the curve for Pb in the absence of other co-existing elements. Fe, as the co-existing element, did not influence the atomization of Pb. For an Ni-Pd alloy, having different characteristics to that of the above-mentioned alloys, the temperature of the sample rose, reached the melting point of Ni (of Pd), formed a molten alloy and then followed flash atomization, as if an explosion had occurred. This was because the melting point of the alloy was lower than the 100% Ni (or Pd) metal.