Insight Into Electrothermal Atomization Mechanism of Several Transition Metals (Cr, Cu,Mn,Ni,Zn) in Uranium and Thorium Matrices: GFAAS Study

摘要

To understand the reason behind the suppression of analyte absorbance in the presence of ranium and thorium matrices, studies were taken up to understand the reaction mechanism for Cr, Cu, Mn, Ni, and Zn analytes with andwithout matrices. Reaction mechanisms were. proposed for atom formation using Arrhe- nius plots. Investigations reveal that the activation energies for these analytes in uranyl and thorium nitrate solutions are similar o those obtained in pure aque- ous solutions and, hence, similarity in the atomization mode for all of these elements. With a view to understanding the suppressive effect due to the matrix, investigations were carried out using scanning electron microscopy(SEM) on the products formed on atomiza tion for Cr, Cu, Mn, Ni, and Zn in aqueous, uranium, and thorium matrices. The investiga- tions reveal that uranium and tho- rium matrices react with the graphite atomizer surfface, leading to the formation of an uneven surface which affects the atomization efficiency, while an aqueous solution does not create any defect on the surface.