Ultra-trace Measurements of 210Pb in natural occurring radioactive materials by ICP-MS

Collision cell inductively coupled plasma mass spectrometry (CC-ICP-MS) was investigated as a possible alternative to nuclear analytical techniques for the determination of 210Pb. The formation of isobaric and polyatomic interferences was studied. Following the acid digestion, extraction chromatography was tested to assess their usefulness in reducing its interferences. A 210Pb pre-concentration of >300-fold and recoveries of 63-73% were obtained using a combined extraction chromatography and pre-concentration by evaporation protocol. Improvement in sensitivity of 210Pb was found by optimization of the collision cell parameters using krypton as a collision gas. The detection limit was improved by a factor of 300 for 210Pb. A detection limit of 0.214 ppt (0.698 Bq/mL) was obtained. The method was applied to determine 210Pb in samples of naturally occurring radioactive materials (NORM).