Trace Elemental Analysis of Bulk Thorium Using an Automated Separation–Inductively Coupled Plasma Optical Emission Spectroscopy Methodology

Abstract

Presented here is a novel automated method for determining the trace element composition of bulk thorium by inductively coupled plasma–optical emission spectroscopy (ICP-OES). ICP-OES is a universal approach for measuring the trace elemental impurities present in actinide-rich materials; however, due to the emission rich spectrum of the actinide, a separation from the trace elements is warranted for spectrochemical analysis. Here, AG MP-1 ion exchange resin was utilized for retention of the Th matrix, while allowing the trace element impurities to be separated prior to subsequent analysis using ICP-OES. After demonstrating the separation on traditional gravity-driven columns, the methodology was transitioned to an automated platform for comparison. This automated platform utilizes syringe-driven sample and solvent flow and can collect the trace element and thorium fractions in separate locations. While reducing the sample size (500 µL, 1.5 mg of Th), maintaining the overall separation efficiency (recoveries >95%), and illustrating the sample throughput ability (n = 10+), this automated methodology could be readily adopted to nuclear facilities in which the determination of trace elemental impurities in Th samples is warranted.

Analysis of solid uranium particulates on cotton swipes with an automated microextraction-ICP-MS system

“…[1][2][3][4] Automation has been increasingly explored in nuclear laboratories as a way of increasing sample throughput and minimizing personnel radiation exposure. 5 Our laboratory has placed an emphasis on automated and rapid analytical methods for analyzing trace elements in bulk uranium/thorium samples, [6][7][8][9] analyzing trace ssion products in a variety of complex radiological matrices, [10][11][12][13] and separating U and Pu in environmental swipe samples. 14 Particle analysis methods, utilized in a host of nonproliferation and safeguards activities, are also being improved by automation.…”

Automated method for concurrent determination of thorium (230Th, 232Th) and uranium (234U, 235U, 238U) isotopes in water matrices with ICP-MS/MS

“…The separation method of Th and/or U from environmental samples based on automatic systems has drawn researchers' interests in recent years. 22,23,[27][28][29][30] Miyamoto et al 23 sequentially separated ultra-trace U, Th, Pb, and lanthanides using an automatic system integrated with an anion-exchange resin MCI-GEL. Th and U were sequentially eluted with 12 M CH 3 COOH-1 M HCl-0.1 M HF and 0.2 M HCl-1 M HF, respectively, to reach nearly quantitative recoveries of Th and U. Higginson et al 27 conducted a radiochemical analysis of trace actinides, including Am/Cm, Np, Pu, and U through UTEVA resin.…”

Analysis of trace elements in uranium by inductively coupled plasma-optical emission spectroscopy, design of experiments, and partial least squares regression

“…[4][5][6] Trace elemental analysis by each technique is generally performed by diluting samples such that the U matrix is low, and matrix matching the calibration standards, 1 or separating the matrix completely. 7 ICP-OES analytical data comes from the emission spectra of elements excited within a plasma with temperatures as high as 10 000 K. The ICP-OES method measures photons, rather than ICP-MS which measures ions of specic mass and is limited by emission rich f-block elements (e.g., U and Pu), which could interfere with trace element spectra.…”

“…Thus, separation technologies including solvent extraction and ion exchange chromatography have been developed to minimize spectral interferences resulting from high concentrations of U relative to the trace elements. [7][8][9][10][11][12][13][14][15] Recent efforts have focused on minimizing sample size, reducing method time, and automation to improve these highly effective separations. 2 Separations are generally assumed to be the superlative way to obtain quality ICP-OES results for each element at all trace-level concentrations.…”