Determination of Trace Amounts of Indium in High-Purity Aluminum by Graphite-Furnace Atomic Absorption Spectrometry after Solvent Extraction and Micro-Volume Back-Extraction

Abstract

A method is described for the determination of trace amounts of indium in high-purity aluminum. Indium in an aluminum solution is extracted into xylene as its diethyldithiocarbamate complex and subsequently back-extracted into 100μl of nitric acid for the determination by graphite-furnace atomic absorption spectrometry (GFAAS). The extraction and back-extraction allow indium to be concentrated by about 2-10-fold from 0.2-1g of aluminum. The resulting solution is suitable for the determination of indium by GFAAS. The detection limit for indium was found to be 0.36ng g^-1 when 0.2g of an aluminum sample was used. The contents of indium in two real high-purity aluminum samples were found to be 0.88 and 10.9ng g^-1.