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

Abstract

A method for determining trace amounts of silver in high-purity aluminum is described. Silver in an aluminum solution is extracted into xylene as its diethyldithiocarbamate (DDC) complex, and subsequently back-extracted into 200μl of nitric acid for a determination by graphite-furnace atomic absorption spectrometry (GFAAS). Silver can be completely extracted from an aluminum solution into xylene over a pH range of 2.5 to 4, and for a DDC concentration of over 4×10^-3mol l^-1. The resulting solution, back-extracted with nitric acid, is suitable for the determination of silver by GFAAS. The detection limit for silver was found to be 1.4ng g^-1 when 0.2g of an aluminum sample is used. The application of this method to the trace analysis of silver in high-purity aluminum samples is demonstrated.