Abstract
A separation scheme for lead and uranium is described. Before the separation of lead, uranium was collected using columns with a conventional method, namely, the separation and collection of uranium were conducted using 6 M and 0.5 M hydrochloric acid, respectively. This process separated lead from iron, thallium, and probably bismuth, which would suppress lead ionization in a thermal ionization mass spectrometer (TIMS). For lead separation, columns with a low ratio of height over inner diameter (H 10 mm, i.d. 4 mm) were employed to strip lead quickly from the resin (AG1-X2 and AG1-X8). Furthermore, 7 M nitric acid was adopted as the eluent instead of the commonly used 6 M hydrochloric acid to achieve a quantitative recovery of lead. These improvements enable us to collect lead with only 0.35 mL of 7 M nitric acid for both types of resin. Recoveries using this method obtained by the measurement of GSJ standard rock samples JA-2 and JA-3 were 96.4% and 99.7%, respectively. Total procedure blanks in two separate runs were 13 pg and 15 pg, respectively. It is therefore suggested that this method is suitable for separation and purification of lead for quantitative and isotopic analyses of geological materials.
