A nuclear forensics investigation involving a uranium ore concentrate relies on accurate and precise analysis of impurities. Analytical data defensibility requires the use of reference materials as ...part of quality control. This study presents a compilation of trace element concentration results of the CUP-2 Uranium Ore Concentrate Standard measured by 11 different laboratories. The laboratories employed various dissolution methods, analytical preparation methods, and instrumental platforms. The data presented here contain concentrations of 66 impurities with up to 138 individual data points for each impurity. Consensus values have been assigned to each impurity following a statistical analysis of the data set.
A new method was developed to effectively separate Am(III) from Cm(III). Am(III) was selectively oxidized to Am(V) using a mixture of Na
2
S
2
O
8
, Ag(I), and NaOCl in 0.01 M HNO
3
. Cm(III) was ...selectively retained on a DGA resin, while Am(V) had no retention. A separation factor of 110 ± 20 was usually obtained from a single separation. The new separation method was applied to determine Cm isotopes 244, 245 and 246 by accelerator mass spectrometry (AMS) in spent nuclear fuel samples.
Effective separation of Am Kazi, Zakir; Guérin, Nicolas; Christl, Marcus ...
Journal of radioanalytical and nuclear chemistry,
07/2019, Letnik:
321, Številka:
1
Journal Article
Recenzirano
A new method was developed to effectively separate Am(III) from Cm(III). Am(III) was selectively oxidized to Am(V) using a mixture of Na.sub.2S.sub.2O.sub.8, Ag(I), and NaOCl in 0.01 M HNO.sub.3. ...Cm(III) was selectively retained on a DGA resin, while Am(V) had no retention. A separation factor of 110 ± 20 was usually obtained from a single separation. The new separation method was applied to determine Cm isotopes 244, 245 and 246 by accelerator mass spectrometry (AMS) in spent nuclear fuel samples.
A novel chronometry method is developed to date irradiated nuclear fuels. It is based on the measurement of two Cm isotopic ratios (
244
Cm/
246
Cm and
245
Cm/
246
Cm) and does not require the ...addition of a yield tracer. The method relies on the decay of
244
Cm while the
245
Cm/
246
Cm ratio is considered constant after irradiation. Feasibility is demonstrated using different types of irradiated fuels with known irradiation history. A precision of 5 year is reached so far but clear potential for improvement has been identified. The novel chronometry method represents a promising alternative to existing dating techniques for nuclear materials.
A new method for determination of the platinum group elements (PGE's: Ru; Rh; Pd; Ir; Pt) in geological samples, using microwave-assisted acid digestion and alkali fusion, separation of the PGE's by ...cation-exchange chromatography, and analysis by inductively coupled plasma-mass spectrometry (ICP-MS) is described. Experiments using synthetic multi-element solutions have been used to establish: conditions for cleaning and conditioning AG 50W-X8 cation-exchange resin; solution requirements for loading samples onto the resin; optimum column size and elution parameters. Recovery studies show no significant retention of Ru, Rh, Pd, Ir and Pt on the resin, at levels ranging from 0.1 μg to 500 μg. Recovery of Au is only complete for solutions containing > 1 μg. Our optimised cation-exchange procedure has been evaluated using 1 g sub-samples of eight reference materials (RM's: DZE-1; DZE-2; MA-2a; PTA-1; PTC-1; PTM-1; SARM7; SU-1a), digested using microwave heating in sealed vessels with aqua regia-HF, followed by alkali fusion of insoluble residues, evaporation of solutions to near dryness, and dissolution in 0.5
M HCl. Matrix elements were removed from sample solutions by cation-exchange chromatography on AG 50W-X8, prior to analysis by ICP-MS. Lower limits of quantitative analysis for 1-g sub-samples range from 1.3 ng g
−1 for Rh to 11 ng g
−1 for Pd, two orders of magnitude better than those achieved for unseparated samples. Good agreement with reference values has been obtained for Ru, Rh, Pd and Ir in most RM's, but Pt results were generally low. Gold is lost on the ion-exchange resin. Preliminary work indicates that, with minor modification, our method may be applied successfully to larger (5 g) sample sizes, and offers an alternative to fire assay for the determination of Ru, Rh, Pd and Ir.
Herein, a nuclear forensics investigation involving a uranium ore concentrate relies on accurate and precise analysis of impurities. Analytical data defensibility requires the use of reference ...materials as part of quality control. This study presents a compilation of trace element concentration results of the CUP-2 Uranium Ore Concentrate Standard measured by 11 different laboratories. The laboratories employed various dissolution methods, analytical preparation methods, and instrumental platforms. The data presented here contain concentrations of 66 impurities with up to 138 individual data points for each impurity. Consensus values have been assigned to each impurity following a statistical analysis of the data set.
Inductively coupled plasma-mass spectrometry (ICP-MS) is an ideal technique for determining the platinum-group elements (PGE's) and An, with rapid data acquisition and low detection limits of ...0.03–0.22 ng ml
−1. Two methods are described for the preparation of geological samples using microwave digestion prior to determination of the PGE's and Au by ICP-MS. In one method, 0.5-g samples are dissolved in sealed all-PFA microwave digestion vessels using HN0
3HCIHFHC1O
4 acids. Samples are transferred to open 'PTFE beakers and evaporated to incipient dryness, final solutions being taken up in 1
M HCI prior to analysis. The method has been evaluated using a suite of well-characterised international reference materials (RM's). In some cases, the method resulted in a complete digestion and quantitative data were obtained for Rh, Pd, Ir, Pt and Au, although insufficiently low limits, of determination precluded the determination of all five elements in all materials. In other cases, an insoluble residue remained and recoveries of the PGE's and Au were dependent on the element concerned and the mineralogy of each sample. A second method employs 1-g samples and microwave digestion with aqua regia-HF, in higher-pressure Ultem-jacketed Teflon
® PFA sealed-vessels. Samples are subsequently evaporated to near dryness, digested in 0.5
M HCI, filtered, and the insoluble residues are fused with small quantities of 1:1 Na
2O
2+Na
2CO
3 or Na
2O
2, before being dissolved in 0.5
M HCI. The combined solutions are analysed by ICP-MS. Data obtained for a wide range of RM's showed good agreement with reference values. Both methods provide viable means of quantifying Ru, Rh, Pd, Ir, Pt and Au in mineralised samples, but both are limited by modest lower limits of determination in samples of 0.2–1 μg g
−1 Only the combined microwave digestion-minifusion technique yields fully quantitative data for samples containing refractory minerals.
The available instrumental methods for platinum group element (PGE: Ru, Rh, Pd, Os, Ir, Pt) and gold (Au) determinations are reviewed. Inductively coupled plasma-atomic emission spectroscopy ...(ICP-AES) and ICP-mass spectrometry (ICP-MS) enable rapid, multi-elemental analysis, their instrumental and analytical characteristics being discussed here. The suitability of ICP techniques to quantitatively determine the PGEs + Au is demonstrated. The detection limits by ICP-AES range from 6 to 29 ng.mLsup-1, while those for ICP-MS range from 0.3 to 0.22 ng.mLsup-1, for the individual PGEs + Au. A digestion step is generally required prior to the analysis of geological materials by ICP-AES and/or ICP-MS. Digestion procedures are reviewed, with particular attention to the new method of microwave digestion. A comparative study of three digestion methods was undertaken, a range of well-characterised rock reference materials being used to evaluate open acid digestion, microwave acid digestion and alkali fusion procedures. The precision and accuracy of results obtained by ICP-AES and ICP-MS for 46 elements demonstrates that no single digestion method is universally applicable. It is concluded that the best digestion procedure for PGE-bearing materials is a combination of microwave acid digestion followed by a fusion of the residue. Such a method was developed and its suitability is demonstrated using reference materials containing high levels of the PGEs + Au, which enable their direct determination by solution ICP-MS. Even with the superior sensitivity of ICP-MS, low concentrations of the PGEs + Au in most geological materials preclude the quantitation of unseparated samples. Separation methods which have been used (fire assay, coprecipitation, ion exchange, solvent extraction, distillation) are reviewed. Two ion-exchange methods were developed to separate the PGEs + Au from their associated matrix elements allowing their preconcentration prior to analysis. An anion-exchange method can be used in conjunction with ICP-MS for the separation and determination of ≥1 ng.gsup-1 Ir and> 1 mug.gsup-1 Ru, Rh, Pd, Pt or Au. A cation-exchange ICP-MS procedure can be used to determine the PGEs at a wider range of concentrations. An evaluation using all the available PGE reference materials showed good agreement with reference values in most instances. Stable isotopes were used to evaluate this method and the results confirm that quantitative results may be obtained. The cation-exchange procedure can be scaled-up to larger samples thus enabling the determination of < 1 ng.mLsup-1 of individual PGEs. This is demonstrated using 5 g sub-samples and guidelines are given for further increases in sample size. Slurry nebulisation ICP-MS was developed for the determination of the PGEs + Au in solid samples without a prior digestion stage. An assessment of the method using reference materials demonstrated that quantitative results may be obtained for all seven PGEs + Au at levels above 50 to 200 ng.gsup-1 (depending on the element). This method is ideally suited to the routine analysis of mineralised samples or where only small sample sizes are available.
The available instrumental methods for platinum group element (PGE: Ru, Rh, Pd, Os, Ir, Pt) and gold (Au) determinations are reviewed. Inductively coupled plasma-atomic emission spectroscopy ...(ICP-AES) and ICP-mass spectrometry (ICP-MS) enable rapid, multi-elemental analysis, their instrumental and analytical characteristics being discussed here. The suitability of ICP techniques to quantitatively determine the PGEs + Au is demonstrated. The detection limits by ICP-AES range from 6 to 29 ng.mLsup-1, while those for ICP-MS range from 0.3 to 0.22 ng.mLsup-1, for the individual PGEs + Au. A digestion step is generally required prior to the analysis of geological materials by ICP-AES and/or ICP-MS. Digestion procedures are reviewed, with particular attention to the new method of microwave digestion. A comparative study of three digestion methods was undertaken, a range of well-characterised rock reference materials being used to evaluate open acid digestion, microwave acid digestion and alkali fusion procedures. The precision and accuracy of results obtained by ICP-AES and ICP-MS for 46 elements demonstrates that no single digestion method is universally applicable. It is concluded that the best digestion procedure for PGE-bearing materials is a combination of microwave acid digestion followed by a fusion of the residue. Such a method was developed and its suitability is demonstrated using reference materials containing high levels of the PGEs + Au, which enable their direct determination by solution ICP-MS. Even with the superior sensitivity of ICP-MS, low concentrations of the PGEs + Au in most geological materials preclude the quantitation of unseparated samples. Separation methods which have been used (fire assay, coprecipitation, ion exchange, solvent extraction, distillation) are reviewed. Two ion-exchange methods were developed to separate the PGEs + Au from their associated matrix elements allowing their preconcentration prior to analysis. An anion-exchange method can be used in conjunction with ICP-MS for the separation and determination of ≥1 ng.gsup-1 Ir and> 1 mug.gsup-1 Ru, Rh, Pd, Pt or Au. A cation-exchange ICP-MS procedure can be used to determine the PGEs at a wider range of concentrations. An evaluation using all the available PGE reference materials showed good agreement with reference values in most instances. Stable isotopes were used to evaluate this method and the results confirm that quantitative results may be obtained. The cation-exchange procedure can be scaled-up to larger samples thus enabling the determination of < 1 ng.mLsup-1 of individual PGEs. This is demonstrated using 5 g sub-samples and guidelines are given for further increases in sample size. Slurry nebulisation ICP-MS was developed for the determination of the PGEs + Au in solid samples without a prior digestion stage. An assessment of the method using reference materials demonstrated that quantitative results may be obtained for all seven PGEs + Au at levels above 50 to 200 ng.gsup-1 (depending on the element). This method is ideally suited to the routine analysis of mineralised samples or where only small sample sizes are available.
