Environmental and Human Monitoring of Americium-241 Utilizing Extraction Chromatography and α-Spectrometry

Abstract

Recent developments in extraction chromatography have simplified the separation of americium from complex matrices in preparation for alpha-spectroscopy relative to traditional methods. Here we present results of procedures developed/adapted for water, air, and bioassay samples with less than 1 g of inorganic residue. Prior analytical methods required the use of a complex, multistage procedure for separation of americium from these matrices. The newer, simplified procedure requires only a single 2 mL extraction chromatographic separation for isolation of Am and lanthanides from other components of the sample. This method has been implemented on an extensive variety of "real" environmental and bioassay samples from the Los Alamos area, and consistently reliable and accurate results with appropriate detection limits have been obtained. The new method increases analytical throughput by a factor of approximately 2 and decreases environmental hazards from acid and mixed-waste generation relative to the prior technique. Analytical accuracy, reproducibility, and reliability are also significantly improved over the more complex and laborious method used previously.

Rapid selective separation of americium/curium from simulated nuclear forensic matrices using triazine ligands

“…Radiochemical separation is therefore required in order to avoid isobaric and polyatomic interferences (e.g. 232 U/ 232 Th) in mass spectrometry and/or spectral overlap in radiometric analyses [1][2][3].…”

Sequential Injection Renewable Separation Column Instrument for Automated Sorbent Extraction Separations of Radionuclides

“…Recently, Horwitz et al described a sorbent extraction methodology based on an actinide-selective extractant (0.75 M solution of octyl(phenyl)- N , N -diisobutylcarbamoylmethylphosphine oxide in tri- n -butyl phosphate) immobilized on an inert polymeric support (TRU-resin, Eichrom Industries, Inc.) . Americium separation on TRU-resin can be carried out by loading the sample in nitric acid, washing the column with additional nitric acid to remove the matrix and interferences (e.g., fission products), and eluting the Am(III) with hydrochloric acid. ,, Other tetra- and hexavalent actinides (e.g., Pu, Th, and U) will remain on the column and can be removed from the column by using ammonium hydrogen oxalate (bioxalate) as a complexing eluent. , The chemistry associated with actinide separations on TRU-resin have recently been investigated in a flow injection format …”

Determination of 241Am in Environmental Samples: A Review

“…However, it has been shown that leaching is not appropriate for soil containing refractory fractions. In the case of refractory residues associated with silicate lattices in the soil and air filter [ 46 ], HF in combination with other acids (typically HNO 3 and HClO 4 ) in an open vessel is a good choice for total dissolution of the matrix to release the entire Am content from the soil sample. Careful control of the physical and chemical conditions during total dissolution with an HF–HNO 3 –HClO 4 system is necessary to prevent the formation of insoluble fluorides, such as AlF 3 and CaF 2 .…”