Ultra-trace determination of plutonium in urine samples using a compact accelerator mass spectrometry system operating at 300 kV

Abstract

Accelerator mass spectrometry (AMS) is a very sensitive and robust technique for analysis of long-lived radionuclides. Employment of the AMS technique can reduce the demands on sample preparation chemistry, due to its high rejection of interferences and low susceptibility to sample matrix. This is particularly of interest for ultra-trace determination of ²³⁹Pu in bioassay and environmental samples, as other mass spectrometric methods such as inductively coupled plasma mass spectrometry (ICP-MS) can suffer from isobaric mass interferences by the presence of uranium in the sample. A rapid sample preparation method for analysis of Pu at femtogram levels in large volume urine samples is described. Using the compact ETH AMS Tandy facility operating at ∼300 kV, the method was validated by analysing urine samples spiked with known amounts of ^239/240/241Pu ranging from 1 to 30 fg. The detection limits for the method were estimated to be 0.38 fg for ²³⁹Pu, 0.40 fg for ²⁴⁰Pu and 0.08 fg for ²⁴¹Pu in 1400 mL of urine.