Occupational exposure to plutonium is generally monitored through analysis of urine samples. Typically, plutonium is separated from the sample and other actinides, and the concentration is determined using alpha spectroscopy. Current methods for separations and analysis are lengthy and require long count times. A new method for monitoring occupational exposure levels of plutonium has been developed, which requires fewer steps and overall less time than the alpha spectroscopy method. In this method, the urine is acidified, and a 239Pu internal standard is added. The urine is digested in a microwave oven, and plutonium is separated using an Eichrom TRU Resin column. The plutonium is eluted, and the eluant is injected directly into the Inductively Coupled Plasma–Mass Spectrometer (ICP-MS). Compared to a direct “dilute and shoot” method, a 30-fold improvement in sensitivity is achieved. This method was validated by analyzing several batches of spiked samples. Based on these analyses, a combined standard uncertainty plot, which relates uncertainty to concentration, was produced. The MDA95 was calculated to be 7.0 × 10−7 μg L−1, and the Lc95 was calculated to be 3.5 × 10−7 μg L−1 for this method.
*Radiochemistry Program, University of Nevada Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89145; †Analytical Services & Instrumentation Division, ES&H, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550; ‡Analytical Services & Instrumentation Division, ES&H, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550; §Department of Environmental & Radiological Health Sciences, Colorado State University, 1616 Campus Delivery, Fort Collins, CO 80523-1618.
The authors declare no conflicts of interest.
For correspondence contact: Athena Gallardo, 4505 S. Maryland Pkwy, Las Vegas, NV 89154, or email at email@example.com.
(Manuscript accepted 19 September 2016)