Uranium and thorium as natural radioactive elements are present everywhere in the environment. Their trace levels are also present in various materials, such as copper, used as a shielding material ...in gamma-ray spectrometry, usually located very close to the detector. Ultra-low levels of uranium and thorium in electrolytic copper were determined in this study using radiochemical neutron activation analysis (RNAA) via their induced nuclides U-239/Np-239 and Pa-233, respectively. After irradiation of copper together with uranium and thorium standards, various techniques were used for their separation from the matrix. To isolate of short-lived U-239, solvent extraction in a combination of tributyl phosphate (TBP) in toluene was used. To separate Np-239 and Pa-233, extraction chromatography using TEVA and TK-400 resins was applied. Special attention was paid to the estimation of radiochemical recovery, which was determined in each sample aliquot using U-235, Np-238 and Pa-231 tracers. For quantification of induced nuclides and tracers used in the experiment, gamma-ray spectrometry was used. Obtained results showed that electrolytic copper samples contained impurities of uranium and thorium in ultra-trace levels: up to 45 pg/g (550 nBq/g) for uranium and up to 80 pg/g (330 nBq/g) for thorium. The electrolytic copper also contained impurities of Ag, As, Au, Sb, Se and Zn as observed using the k0-INAA technique.
•Ultra low-levels of uranium and thorium in electrolytic copper were determined.•Radiochemical neutron activation analysis was used.•Uranium was determined via its induced nuclides U-239 and Np-239.•Thorium was determined via its induced nuclide Pa-233.•Separations were done with solvent extraction and extraction chromatography.
Primary reference measurement procedure for Cr determination in biological samples by radiochemical neutron activation analysis (RNAA) has been elaborated. The procedure is based on quantitative and ...selective separation of chromium from neutron irradiated sample by column chromatography using MnO
-Resin and determination of
Cr by γ-ray spectrometry. Quality components have been incorporated into the RNAA method which makes it possible to meet the requirements of the definition of ratio primary reference measurement procedure. The usefulness of the elaborated procedure to assign the certified values for Cr in new certified reference material (CRMs) based on animal tissues is demonstrated. The tentative certified values for Cr have been proposed for: MODAS M-4 Cormorant Tissue and M-5 Cod Tissue CRMs.
MnO
2
Resin and Dowex 1X8 manganese dioxide impregnated resin was used for chromium separation from biological samples. We examined sorption of chromium from acid solutions: hydrochloric, nitric and ...sulphuric in concentration range from 0.01 to 2 mol/dm
3
. The sorption process was evaluated by batch and column experiments. We also examined sorption of other elements in the developed systems, to check the selectivity of the process. Determination of chromium by radiochemical neutron activation analysis after separation with MnO
2
Resin was described.
Determination of a low level 237Np in environmental samples was performed by various techniques: i) a direct gamma-ray spectrometry, ii) an alpha-particle spectrometry that followed pre-separation of ...neptunium radioisotope(s) by ion-exchange or extraction chromatography and iii) pre-separation radiochemical neutron activation analysis. The methods used were applied to various reference materials with inorganic and organic matrix as well as to a wide range of neptunium content. The results were compared with reference and literature values.
•Determination of low-level Np-237 is described.•Three different techniques for decomposition of samples were compared.•Separations were done with ion exchange and extraction chromatography.•γ-ray spectrometry, α-particle spectrometry and pre-separation RNAA were compared.
A radiochemical neutron activation analysis procedure was developed for the determination of trace amounts of gold in biological materials. The procedure was realized with irradiation of reference ...and test samples in a nuclear reactor, selective and quantitative separation of gold using inorganic MnO
2
Resin and gamma-ray spectrometric measurement of
198
Au. The method is characterized by a low limit of detection of gold at ng g
−1
level. Results shows that the method can be applied to the determination of trace amounts of gold in tissues for medical research.
A procedure based on radiochemical neutron activation analysis was developed for the determination of chromium in biological materials. The procedure consists of irradiation of reference and test ...samples in a nuclear reactor, microwave sample digestion, selective and quantitative radiochemical separations of chromium and gamma-ray spectrometric measurement of
51
Cr. Separation of chromium from the accompanying elements was done on the column packed with inorganic resin MnO
2
Resin. Distribution coefficients of Cr, Zn, Co, Cs and Sc were determined in the system: MnO
2
Resin—HCl, HNO
3
and H
2
SO
4
. Accuracy of the procedure was checked by analysis of certified reference materials.
Determination of environmental tungsten (W) is inhibited by a lack of reference materials and practical methods to remove isobaric and radiometric interferences. We present a method that evaluates ...the potential use of commercially available sediment, Basalt Columbia River-2 (BCR-2), as a quality control standard for W. Tungsten concentrations determined using neutron activation analysis (NAA) and mass spectrometry are in statistical agreement at the significance level α = 0.05 (92 ± 4 ng g
−1
for NAA and 100 ± 7 ng g
−1
for mass spectrometry). These results indicate that BCR-2 may be suitable as a quality control standard for future studies.
Neutron activation analysis (NAA) has been the analytical method of choice for rare earth element (REE) analysis from the early 1960s through the 1980s. At that time, irradiation facilitieswere ...widely available and fairly easily accessible. The development of high-resolution gamma-ray detectors in the mid-1960s eliminated, formany applications, the need for chemical separation of the REE from the matrix material, making NAA a reliable and effective analytical tool. While not as precise as isotopedilution mass spectrometry, NAA was competitive by being sensitive for the analysis of about half of the rare earths (La, Ce, Nd, Sm, Eu, Tb, Yb, Lu). The development of inductively coupled plasma mass spectrometry since the 1980s, together with decommissioning of research reactors and the lack of installation of new ones in Europe and North America has led to the rapid decline of NAA.
Radiochemical neutron activation analysis coupled with the
k
0-standardization method (
k
0-RNAA method) was applied to silicate rock samples for the simultaneous determination of trace halogens (Cl, ...Br and I). Analytical results obtained by the
k
0-RNAA method for geological standard rocks and meteorite samples agreed with those determined by the conventional comparison method conducted in the same set of experiments, suggesting that the
k
0-RNAA method is as reliable as the conventional method. Our data for these samples are in good agreement with their literature values except for rare cases. Detection limits calculated under the present experimental condition are sufficiently low for Cl and Br but not for I for typical geologic and meteoritic samples. The
k
0-RNAA method coupled with longer neutron-irradiation is expected to yield satisfactorily low detection limits for halogens including I in these samples.
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