“…[12][13][14][15] Unfortunately, these radiometric approaches have a significant time requirement for counting (up to a day per sample) and do not allow for the discrimination between 239 Pu and 240 Pu isotopes. Ion-counting instruments such as secondary ion mass spectrometry (SIMS), 16 resonance ionization mass spectrometry (RIMS), 17 thermal ionization mass spectrometry (TIMS), 8,14,18,19 accelerator mass spectrometry (AMS), 20,21 and inductively coupled plasma mass spectrometry (ICP-MS) 9,[22][23][24][25][26][27][28][29][30][31] have also been used to determine Pu isotopes in urine. Because ICP-MS can directly ionize analytes contained in an aqueous matrix, it is therefore understandable that this technique is principally used for the development of rapid analytical methods for Pu urinalysis.…”