SELECTIVE EXTRACTION AND ONE-DROP FLAME ATOMIC-ABSORPTION SPECTROMETRIC DETERMINATION OF TRACE AMOUNTS OF SILVER IN HIGHLY-PURE COPPER AND LEAD

After the dissolution of copper and lead in sulfuric or nitric acid, s ilver was selectively extracted as a ternary silver-1,2-bis(ethylthio) ethane-picrate complex into a small volume of chloroform at pH 1.0-1. 5, leaving copper and lead in an aqueous solution without a masking ag ent. Direct nebulization of 50 mu l of the chloroform extract into a f uel-lean air-acetylene flame gave a sensitive signal height without ba ckground correction from chloroform. The present method was successful ly applied in the determination of silver in copper and highly-pure co pper and lead metals.