Rapid and automated sequential determination of ultra-trace long-lived actinides in air filters by inductively coupled plasma mass spectrometry

A novel, rapid and completely automated method for the determination of long-lived actinides in air particulate samples was developed using ion chromatography separation prior to ICP-MS analyses. U, Pu and Am were pre-concentrated and separated from radioactive and stable interferences through a sequential arrangement of three columns (TEVA, U/TEVA, DGA) arranged in order to allow selective retention of the radioisotope on the designated resin. Detection and quantification of the various radioisotopes were performed on-line using inductively coupled plasma mass spectrometry (ICP-MS). Detection limits of 0.0006 (²³⁸U), 0.0063 (²³⁹Pu), 0.0041 (²⁴⁰Pu), 0.062 (²⁴¹Am) μBq/m³ were obtained for air filters (based on 3000 m³ of air filtered). The automated procedure has been successfully tested on SRMs and spiked samples and showed high recovery yields (>90%). A total analysis time of 18 min is required for the separation, detection, and column rinsing/regeneration for subsequent analysis.