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.