Application of a high resolution inductively coupled plasma mass spectrometer to the measurement of long-lived radionuclides

Abstract

Some long-lived radionuclides, such as ⁹⁹Tc, ²²⁶Ra, ²³²Th, ²³⁷Np, ²³⁸U, ²³⁹Pu and ²⁴⁰Pu were measured using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). By using HR-ICP-MS with an ultrasonic nebulizer, the detection limits of these nuclides were 0.002–0.02 pg ml^–1 and the sensitivities were 10 times better than those obtained using HR-ICP-MS without the ultrasonic nebulizer. More accurate isotopic data were also obtained using HR-ICP-MS than with quadrupole ICP-MS at lower concentrations of the analyte because of the improvement in counting statistics that can be obtained with HR-ICP-MS due to the greater efficiency of ion transmission. A comparison of the measurement of the ²⁴⁰Pu to ²³⁹Pu ratio is shown.