RADIONUCLIDE BIOASSAY BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY(ICP MS)/

Inductively coupled plasma mass spectrometry (ICP/MS) is a sensitive, efficient, and versatile means of elemental analysis that is becoming an acceptable method for measuring long-lived radionuclides in various media. As with other spectrometric techniques, ICP/MS detects atoms r ather than the radioactive emissions associated with radionuclides. Th us, it is not limited by the decay characteristics of radioactive mate rials (e.g. low specific activity). The feasibility of using ICP/MS ha s been investigated as an alternative method for measuring selected ra dionuclides (Np-237 and Pu-239) in urine. When used in conjunction wit h the described separation procedures, ICP/MS provides detection limit s similar to or lower than those provided by conventional alpha spectr ometry. In addition, the time required to determine the amount of a ra dionuclide in a sample is short compared with that for alpha particle counting. Continuing research on instrument design and sample-introduc tion techniques shows promise for further reducing detection limits, w hile ameliorating, or even eliminating, some of the current limitation s of this technique.