Abstract
Sensitivity of the determination of microamounts of lead in iron oxide by atomic absorption spectrometry has been improved by an employment of organic solvent extraction.
Two tenth gram of sample is dissolved in hydrochloric acid and nitric acid. The solution is evaporated to near dryness (ca. 2 ml) with 1000 μg of manganese, and, after cooling, 5 ml of ammonium citrate solution (30%) and 5 ml of DHEG solution (10%) are added. The pH is adjusted to about 10 with ammonia water (28%).
It is transferred into a separatory funnel, and shaken with 5 ml of dithizone(0.1%)-MIBK solution for one minute. The extract is subjected to atomic absorption spectrometry. Five hundreds μg each of Mn, Cr, Co, Ni and Zn and 200 μg of Cu do not interfere with the determination.
The method is recommended for the rapid determination of extremely low concentration (0.00010.0100%) of lead in iron oxide, with the coefficient of variation_ about 3%.
