Quadrupole and multi-collector ICP-MS analysis of 226Ra in brain from a radium dial painter

Abstract

Two ICP-MS methods were developed to measure the radiotoxic isotope ²²⁶Ra in brain tissues from a radium dial painter worker. The first method was a direct analysis of acid digested samples using quadrupole ICP-MS. The instrumental LOD of ²²⁶Ra was 0.1 ng kg⁻¹. Polyatomic interferences at m/z 226 were investigated and Pb was identified from a polyatomic interferent in an in-house sample prepared from bovine brain, with a 226/208 formation ratio of 4 × 10⁻⁸. The quadrupole ICP-MS method was also used to measure levels of beryllium, strontium, and uranium. A second method was developed that included cation-exchange chromatography to separate ²²⁶Ra followed by analysis with sector field MC-ICP-MS. The instrumental LOD for the cation exchange method with MC-ICP-MS detection was 0.5 pg kg⁻¹ (19 mBq kg⁻¹). The measured concentrations of ²²⁶Ra in different brain regions ranged from 0.09–0.72 ng kg⁻¹ (3.3–27 Bq kg⁻¹) and radium was non-uniformly distributed in the brain.