Rare Earth Elements In Samples Research Articles

Distribution of Trace and Rare-Earth Elements, and Nd, Pb, and Sr Isotopes in the Surface Sediments of the Barents Sea

Abstract—The distribution of Sc, Co, Hf, Cr, Th, and rare-earth elements in samples of surface sediments collected during cruises 67th and 68th of the R/V Akademik Mstislav Keldysh in the Barents Sea and in its bays is analyzed. The results obtained suggest that the predominant part of the bottom sediments of the Barents Sea is composed of thin-grained siliciclastics that was supplied with suspended particulate matter of the North Cape (Atlantic) Current through the erosion of the northwestern Scandinavian coasts and some seafloor areas. Some sediments in the northern part of the sea were formed through the erosion of rocks of the Novaya Zemlya and Franz Josef Land. A certain role in their formation was probably played by material from Svalbard as well as by the Pechora River suspended particulate matter. The established isotopic characteristics (eNd, 207Pb/206Pb and 87Sr/86Sr) of surface sediments suggest that the main contribution to the formation of bottom sediments of the central Barents Sea was made by rocks of the mainland part affected by the North Cape Current. The comparison of the 87Sr/86Sr values ​​in the surface sediments of the central part of the Barents Sea and in the ice-rafted sediments carried by the Transpolar Drift showed their significant difference. This suggests a reatively small contribution of ice-rafted material to the formation of surface sediments of the Barents Sea.

Seasonal changes in concentrations of trace elements and rare earth elements in shoot samples of Juncus effusus L. collected from natural habitats in the Holy Cross Mountains, south-central Poland

Selected trace elements (Ag, As, Ba, Bi, Cd, Co, Cr, Mn, Cu, Fe, Ni, Pb, Tl, U, Zn) and rare earth elements were determined in 13 samples of Juncus effusus collected from three investigation sites in the Holy Cross Mts., south-central Poland. Sampling was carried out four times during a vegetative season of 2014. Almost all the elements examined showed different seasonal trends in their concentrations, except for Ag, Co and Ni. Maximum concentrations of Ag in samples of three investigation sites were found in May (0.068, 0.062, 0.047 mg/kg) whereas Co (0.124, 0.070, 0.079 mg/kg) and Ni (1.8, 0.998, 2.8 mg/kg) in July, respectively. Mean concentrations of Mn and Cd were higher in shoots (558 and 2.35 mg/kg) than in roots (435 and 1.7 mg/kg). Both these elements revealed much higher concentrations in J. effusus than their typical contents in plant samples. Principal component method allowed us to allocate Ni, Ba, Cd and Cu to one group with the highest positive loadings. The most probable explanation for this correlation is that bioavailability of these metals is increased by J. effusus through a release of oxygen to the rhizosphere. Light rare earth elements concentrations predominate over heavy rare earth elements in the samples examined. A fractionation of lanthanides occurs during their transport from roots to shoots, although this transport is rather limited. All shoot samples have a strong positive Eu anomaly.

Development of ICP-MS and ICP-OES methods for determination of gadolinium in samples related to hospital waste water treatment

AbstractA suitable analytical method making possible the determination of Gd and other rare-earth elements in samples related to hospital waste water treatment was sought with regard to various aspects of the experiment aimed at monitoring the fate of Gd-based contrast agents in the aquatic environment. The discrepancies and pitfalls of the proposed methodology were considered, resulting in a functional experimental plan. The inductively coupled plasma mass spectrometry (ICP-MS) method was used for the determination of Gd and other rare earth elements in river and hospital waste water and algae

The use of k0-NAA for the determination of the n( 235U)/ n( 238U) isotopic ratio in samples containing uranium

In the analysis of rare earth elements in samples containing uranium by k 0-neutron activation analysis fission of 235U was considered an undesired phenomenon until the “fission k 0-factors” were introduced to account for natural-U fission interferences. In this work, by using a reverse perspective of the problem, the observed 235U-fission and 238U activation products (along with the k 0-factors) were used to obtain information about the n( 235U)/ n( 238U) 1 1 Definition: n(X) refers to the isotopic abundance of isotope X isotopic ratio in the samples. The relevant formulae and data-filtering algorithm were implemented in a home-made computer software, allowing automated evaluation and selection of unbiased data. Two radioisotopes ( 131I and 140La) were demonstrated to be reliable candidates for n( 235U)/ n( 238U) determination in environmental samples. The accuracy of this method was determined using several isotopic standards varying from a depleted to a highly enriched 235U content. An overall 2.31±0.03% overestimation of the isotopic ratio was observed (within 95% confidence level).

A search for rare and other trace elements in different stages of a copper mill by NAA

A method has been developed for the determination of Re, Se, As, Sb, Pt, Au, Te and Rare Earth elements in samples collected at various stages during the production of copper. Instrumental neutron activation analysis, along with a multielement sequential procedure for radiochemical separation of these analytes has been worked out and the results for various samples are discussed.

Wall-stabilised plasma arc applied to the determination of rare earth elements in phosphate samples

A wall-stabilised plasma arc seeded with potassium chloride has been used as an excitation source for the spectrographic determination of rare earth elements in samples of phosphate deposits. The samples were treated with a mixture of HNO3 and HF in a Teflon decomposition vessel and then with H2SO4. The effect of the sample matrix on the excitation temperatures in the plasma and on the analytical curves obtained was studied. The results from the analysis of 12 samples, collected from the Abu Tartur plateau, Western Desert, Egypt, are given. The normalised rare earth patterns reveal a marine environment for deposition.

Determination of rare earth elements by ion pair HPLC with post-column derivatization using Arsenazo III

Rare earth elements can be determined on a CGC column 3 x 150 mm packed with Separon SGX C 18 modified with sorbed ammonium dodecyl sulfate (from solutions with c = 5 mmol l-1) by isocratic or stepwise gradient elution with ammonium DL-α-hydroxyisobutyrate solution (20-160 mmol l-1) at pH 4·5. The method of post-column derivatization with a solution of Arsenazo III (5 μmol l-1) in 0·1M formate buffer at pH 2·9-3·0 for photometric detection enables 10-150 or 6-155 ng of rare earth ions in sample (n = 5-7). By preconcentration on the analytical column from 0·1-2·5 ml sample volumes followed by stepwise gradient elution, 30-80 μg of rare earth ions in 1 ml sample can be determined with a reproducibility of 4% or better, the recovery being 90-106%. The procedures were applied to the determination of rare earth elements in samples of apatite, oxide concentrates and a luminophor, and a very good agreement with the results obtained by optical methods was achieved.

X-ray flurorescene (XRF) determination of trace rare-earth elements in geological samples using ion-exchange-resin membrane technique

Rare-earth elements in samples of geological interest were separated from other elements and concentrated onto ion-exchange membrane through ion-exchange procedures. The membrane was then used to determine the REE by X-ray fluorescence spectrography. In comparison with the traditional “thick-specimen” approach, the requirement of sample (REE oxides) in this method was reduced from 10 to 1 mg. Variable-internal-standard-quantification method was adopted to determine the relative concentrations of REE collected on the membrane. The area density of the sample was controlled at about 0.0003 g/cm2, so that the matrix effect could be eliminated to a satisfactory extent. Interference calibration between the spectro-lines and the background determination was also improved, with the detection limit reaching 2.5×10−6g.