Solid–liquid extraction for the determination of impurities in high-purity lead by atomic absorption spectrometry with electrothermal atomization

Abstract

After dissolving a lead sample in 4.5 mol l^–1 nitric acid, the solution was evaporated to dryness. The trace impurities were extracted from lead nitrate crystals with an ethanolic solvent, that is, a 99 + 1 mixture of ethanol (99.5% v/v) and 15 mol l^–1 aqueous ammonia (for silver) or a 99 + 1 mixture of ethanol (99.5% v/v) and 12 mol l^–1 hydrochloric acid (for iron, copper and cadmium). The desired trace metals were recovered in >93% yields and determined by electrothermal atomic absorption spectrometry. The separation factor for the lead matrix was about 10^–3. The proposed method was applied to the determination of impurities at ng g^–1 levels in high-purity lead metal.