Simultaneous determination of Po and Pb in solid samples: A new method for Pb determination.

A new method has been developed for determination of Pb and a simultaneous determination of Po and Pb was performed in solid samples. Po and Pb were sequentially leached at 250 °C with HNO+HF, HClO and HCl. Twenty percent of the leaching solution was used for Po determination by α-spectrometry after Po spontaneous deposition on a silver disc from a weak HCl solution that containing hydroxylamine hydrochloride, sodium citrate and Po tracer. The remains of the leaching solution were used for determination of Pb, conducted by precipitation as PbCrO at about pH < 4, purification with an anion-exchange resin column, source preparation as PbSO, and measurement with a β-counter. The procedure has been checked with the IAEA-327, a certified reference material, showing good agreement with the recommended values. The lower limits of detection for 3 g soil sample were found to be 0.17 Bq kg for Po and 0.92 Bq kg for Pb. A variety species of soil and sediment samples have been analysed using the procedure, showing average yields of 95.2 ± 2.6% for Po and 91.0 ± 8.3% for Pb.