Determination Of Nd Research Articles

Clay mineral and Nd, Pb, and Sr isotope provenance of a MIS 4-3 sediment record from the Lomonosov Ridge, central Arctic Ocean

Modern techniques for detrital mineral provenance were applied to sediment core 96/12-1pc from the Lomonosov Ridge in the central Arctic Ocean. The techniques include quantitative clay mineralogy analysis combined with determination of Nd, Pb, and Sr isotopes from clay fraction. The clay mineral assemblage and the isotope signatures depict distinct changes during the Marine Isotope Stage (MIS) 4-3 transition corresponding to the Middle Weichselian deglaciation. This transition is characterised by a homogenous, 48 cm thick, dark grey, silty clay layer with a distinctive IRD concentration, forming a prominent marker bed for the central Arctic Ocean sediments. The elevated smectite and kaolinite contents in the transitional interval are possible weathering products of the Siberian basaltic rocks, such as the Putorana Plateau, feeding the shelves of the Kara Sea and the western Laptev Sea. The Nd and Sr isotope values are compatible with input from the basaltic rocks and fall within the isotopic range of sediments from these shelves. The abrupt changes in the Nd, Pb and Sr isotopic data from the distinct grey layer attributed to the MIS 4-3 transition likely mark a pronounced deglaciation event. An increase in coarse debris in the grey layer indicates a change in the sedimentation regime with a strong iceberg rafting component. This change may also be related to a sudden release of meltwater from a large ice-dammed lake in the northern Siberia.

Comparative Spectrophotometric Determination of Neodymium (III), Praseodymium (III), Samarium (III) and Terbium (III) in Aqueous and Micelle Media

This research work titled comparative spectrophotometric determination of neodymium (III), praseodymium (III), samarium (III) and terbium (III)in aqueous and micelle media using schiff base was carried out with the aim to use a simple, rapid and sensitive spectrophotometric method for the determination of Nd (III), Pr (III), Sm(III) and Tb(III) using the Schiff base 2,2′-((1E,1′E)-(1,2-phenylenebis(azanlylidene)bis (methanylylidene))diphenol (BSOPD) as a ligand. Spectral and absorbance measurements were carried out using UV/Visible Spectrophotometer (Jenway model no.: 6305) with 1-cm matched quartz cells. This method of experiment was based on the formation of green coloured complexes, upon the reaction of Nd(III) and Pr(III) and a brown coloured complexes for Sm(III) and Tb(III) having a maximum absorbance of 376, 386, 384 and 380 nm respectively. The comparative analysis of the complexes formed in aqueous and in micellar media were investigated in this study. In the obtained results, it was discovered that, Beer’s law was obeyed in the concentration ranges of 0.001 - 0.02 ppm. The molar absorptivity was found to be in the range of 7,776- 23,197 and 27,087 dm³mol^-1cm^-1 and the Sandell’s sensitivity for the compounds analyzed were in the ranges of 6.13-19.34 g cm^-2. The increase in absorbance in the presence of the surfactants is due to micelle formation. The reactants were bound in a small volume of stern layer of the micelle leading to a greater increase in concentration effect. This effect in concentration reaches a maximum before decreasing due to dilution effect occasioned by increase in metal ion concentration.

Resolving isobaric interference in the determination of Nd isotopes using laser ionisation mass spectrometry towards atom percent fission measurements

Use of LIMS for determination of Nd in the presence of Sm.

Chemical Characterization in the Production Chain of Permanent Magnets by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) – Precise Quantification of Nd, Pr, Fe and B in Super-Magnets Samples

Super-magnets, materials whose strong magnetic activity is an attractive differential for the high-tech industry, may have their magnetic performance affected by small variations in their chemical composition. For example, the neodymium and praseodymium content can change the physicochemical properties of the permanent magnets. Aiming at a strict chemical quality control, this work developed an analytical method to quantify the major elements in the materials involved in the production process of didymium (the mixture of neodymium and praseodymium) super-magnets. The simultaneous determination of Nd (401.225 nm), Pr (414.311 nm), Fe (259.837 nm) and B (249.678 nm) in three different sample types (didymium oxide, metallic didymium and (Nd,Pr)-Fe-B alloy) was performed by sample dissolution in acidic media, followed by instrumental measurements using an Inductively Coupled Plasma Optical Emission Spectrometer. Linear calibration curves were obtained with high coefficient of determination (0.9983 ≤ R2 ≤ 0.9999) and with appropriate limits for determining these elements at the percentage level, reaching detection limits less than 0.07 cg g-1. The precision of the method was improved by weighing of the solutions during all the dilution steps and was evaluated by the coefficient of variation associated to instrumental precision (0.3 – 0.7%), method intermediate precision (1.9 – 3.1%) and also by the typical mass fraction provided as uncertainty (0.04 – 0.20 cg g-1), reaching the pressing need to distinguish the content of the rare earth elements in less than 1 cg g-1. The accuracy of the method was assessed by spiked and recovery test (96-104% for spikes equal to or greater than 0.50 cg g-1) and also by the use of different analytical methods, involving the participation of other laboratories, obtaining an acceptable degree of agreement (85 – 107%).

A New Highly Selective Neodymium(III) Polyvinylchloride Membrane Electrode Based on 4-Hydroxypyrrolidine-2-Carboxylic Acid as an Active Material

The present paper describes the fabrication of a new polyvinylchloride (PVC) membrane electrode for the determination of Nd(III) ion based on 4-hydroxypyrrolidine-2-carboxylic acid (LHP) as an active material along with sodium tetraphenyl borate (NaTPB) as an anionic additive and acetophenone (AP) as solvent mediator. The optimum composition (%, w/w) of the best performing membrane contained 66 AP, 30 PVC, 2 NaTPB and 3 LHP. The basic analytical parameters of this electrode such as slope characteristics, detection limit, response time, selectivity and pH effect were assessed. The electrode displayed a Nernstian response in terms of slope (20.5 ± 0.4 mV per decade) and response time (~8 ± 1 s) over a wide neodymium ion concentration range of 10–6 to 10–2 M with a detection limit of 7.5 × 10−7 M. The potentiometric response of the electrode was constant in the pH range of 3.2‒8.9. According to the selectivity coefficients determined by the matched potential method, the interference of many common alkaline, alkaline earth, transition, heavy metals and specially lanthanide ions in determination of Nd(III) ion was very low. The proposed electrode has been successfully used as an indicator electrode in the potentiometric titration of Nd(III) ion with EDTA and applied for determination of Nd(III) ion in mixtures of different ions.

UV Radiation Detection Using Optical Sensor Based on Eu3+ Doped PMMA

AbstractProgress in UV treatment applications requires new compact and sensor constructions. In the paper a hybrid (organic-inorganic) rare-earth-based polymeric UV sensor construction is proposed. The efficient luminescence of poly(methyl) methacrylate (PMMA) matrix doped by europium was used for testing the optical sensor (optrode) construction. The europium complex assures effective luminescence in the visible range with well determined multi-peak spectrum emission enabling construction of the optrode. The fabricated UV optical fibre sensor was used for determination of Nd:YAG laser intensity measurements at the third harmonic (355 nm) in the radiation power range 5.0-34.0 mW. The multi-peak luminescence spectrum was used for optimization of the measurement formula. The composition of luminescent peak intensity enables to increase the slope of sensitivity up to −2.8 mW-1. The obtained results and advantages of the optical fibre construction enable to apply it in numerous UV detection systems.

Determination of Nd:YAG laser parameters for metal threads cleaning in textile artefacts

Textile samples with metallic threads from the collection of the Ethnographic Museum Belgrade were subjected to Nd:YAG laser irradiation in order to determinate certain parameters for successfully and safely clean corrosion products without degrading the surrounding material. Application of conventional cleaning methods did not give the expected results, and the implementation of laser technology was the next step. The Nd:YAG laser energy 150 mJ (1064 nm) and 50 mJ (532 nm) and pulse width 150 ps was used. The commercial, Thunder Art Laser was also used. Effects of the irradiated areas was investigated by optical and SEM microscopy and EDX analysis.

Addendum to the AAPM's TG-51 protocol for clinical reference dosimetry of high-energy photon beams.

An addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water in megavoltage photon beams is presented. This addendum continues the procedure laid out in TG-51 but new kQ data for photon beams, based on Monte Carlo simulations, are presented and recommendations are given to improve the accuracy and consistency of the protocol's implementation. The components of the uncertainty budget in determining absorbed dose to water at the reference point are introduced and the magnitude of each component discussed. Finally, the consistency of experimental determination of ND,w coefficients is discussed. It is expected that the implementation of this addendum will be straightforward, assuming that the user is already familiar with TG-51. The changes introduced by this report are generally minor, although new recommendations could result in procedural changes for individual users. It is expected that the effort on the medical physicist's part to implement this addendum will not be significant and could be done as part of the annual linac calibration.

Cross-validation of analytical procedures for the reliable determination of Nd concentrations in nuclear fuel using ICP-OES and sector field ICP-MS

This study focussed on the development and validation of straightforward ICP-OES and sector field ICP-MS procedures for the accurate determination of the neodymium (Nd) concentration in nuclear samples. After dissolution of a spent fuel in a chemical hot cell, Nd was analysed in the acidic solution without prior separation of any fission products. In order to improve sensitivity, a high efficiency sample introduction system was coupled to the employed high resolution ICP-OES instrument. The ten most sensitive emission wavelengths of Nd were investigated systematically, all of them yielding detection limits (LODs) of less than 1 μg kg−1. The highest sensitivity and the best LOD of 0.3 μg kg−1 were obtained at the emission lines λ = 401.225 nm and λ = 430.358 nm. Compared to previous studies this LOD is more than one order of magnitude lower while sample consumption (∼0.3 mL min−1) is less than one third of the volume normally required for such analysis. In terms of radioactive samples these improved analytical figures of merit denote a considerably lower dose to the ICP-OES operator and less radioactive waste. Considering sensitivity, potential spectral interferences and stability of the spectral background, the four emission lines at λ = 401.225 nm, λ = 406.109 nm, λ = 410.946 nm and λ = 430.358 nm proved to be most useful for the reliable determination of Nd. In the absence of matrix matched reference materials having a certified Nd concentration, the accuracy of Nd ICP-OES analysis was ascertained by quantification of Nd using both external calibration and the standard addition approach. In addition, sector field ICP-MS analysis of the Nd elemental concentration was also possible without any separation step as the Nd isotopic composition of the spent fuel was well characterised in previous analyses. This new series of ICP-MS analyses was based on the interference-free isotopes 143Nd, 144Nd (a small 144Ce correction was almost negligible), 145Nd and 146Nd, which are also the four main isotopes in fission Nd. The relative isotopic results obtained using sector field ICP-MS confirmed the previously determined Nd isotopic composition. The repeated Nd concentration analysis of the dissolved spent fuel sample applying the developed ICP-OES and ICP-MS procedures gave results that overlapped within their standard deviations, underpinning the reliability of both experimental approaches.

Polymer monolith microextraction coupled to microwave plasma torch–atomic emission spectrometry for the determination of Nd, Eu and Yb in tea samples

A reliable and rapid method based on polymer monolith microextraction (PMME) combined with microwave plasma torch-atomic emission spectrometry (MPT-AES) was established for the determination of trace rare earth elements (REEs), Nd (light), Eu (medium) and Yb (heavy). Several parameters affecting extraction efficiency, including sample pH, sample flow rate, sample volume, eluent concentration, eluent flow rate and eluent volume, were investigated and optimized in detail. Under the optimum conditions, the limits of detection (n = 7) and limits of quantification (n = 7) for Nd, Eu and Yb (based on a 0.8 mL sample volume) were determined to be 1.07, 0.83 and 1.47 μg L−1, and 3.57, 2.78 and 4.90 μg L−1, respectively. The enrichment factors for Nd, Eu and Yb (5 μg mL−1) were determined to be 15.1, 12.8 and 12.5, respectively, with relative standard deviations (n = 7) of 5.10%, 5.43% and 7.84%. The proposed method has been successfully applied to the analysis of Nd, Eu and Yb in tea samples with a recovery range of 81.2–109.2%.

Potentiometric Sensor Array for Analysis of Complex Rare Earth Mixtures

AbstractAn approach for simultaneous quantification of several rare earth elements (RE) in complex mixtures, using an array of cross‐sensitive potentiometric sensors with plasticized polymeric membranes, is reported. 14 different ligands suggested in liquid extraction systems for separation of lanthanides/actinides were employed as membrane active compounds in the polymeric sensors. The sensors of the array were found to have high potentiometric sensitivity towards lanthanide ions in acidic solutions with pH 1.5. The array of 28 sensors was applied for simultaneous determination of three RE metals in four sets of model mixtures simulating technological solutions of spent nuclear fuel reprocessing process. Multivariate calibration models calculated with PLS1 algorithm revealed that analysis of Y, La and Gd in mixtures with uranyl nitrate is possible with RMSEP values 0.29, 0.17 and 0.28 logCMe correspondingly (confirmed by independent test set). Determination of Nd, Sm and Gd in mixtures with uranyl (RMSEP=0.25–0.26 logCMe) and with thorium (RMSEP=0.28–0.37 logCMe) is also possible.

Determination of Nd3+ Ions in Solution Samples by a Coated Wire Ion‐Selective Sensor

A new coated wire electrode (CWE) using 5‐(methylsulfanyl)‐3‐phenyl‐1H‐1,2,4‐triazole (MPT) as an ionophore has been developed as a neodymium ion‐selective sensor. The sensor exhibits Nernstian response for the Nd3+ ions in the concentration range of 1.0×10−6‐1.0×10−2 M with detection limit of 3.7×10−7 M. It displays a Nernstian slope of 20.2±0.2 mV/decade in the pH range of 2.7–8.1. The proposed sensor also exhibits a fast response time of ∼5 s. The sensor revealed high selectivity with respect to all common alkali, alkaline earth, transition and heavy metal ions, including members of the lanthanide family other than Nd3+. The electrode was used as an indicator electrode in the potentiometric titration of Nd(III) ions with EDTA. The electrode was also employed for the determination of the Nd3+ ions concentration in water solution samples.

Neodymium(III)–PVC membrane sensor based on a new four dentate ionophore

A new selective Nd(III) sensor has been made by using N,N′-bis(quinoline-2-carboxamido)-4,5-dimethylbenzene (H2L4) as a suitable ionophore. The sensor exhibits Nernstian response to Nd(III) ions in the concentration range of 5.0×10−6 to 1.0×10−2M. It displays a Nernstian slope of 19.5±0.4mV/decade in the pH range of 2.9–9.2. The proposed sensor also exhibits a fast response time of <l0s. The detection limit of the proposed sensor is 4.8×10−6M, and it can be used over a period of 10weeks without significant changes in its response. Furthermore, the electrode showed high selectivity toward Nd(III) ion respect to all other lanthanide ions tested. The practical utility of the sensor was demonstrated by using it as an indicator electrode in the potentiometric determination of Nd(III) ions in certified reference material and spiked water samples.

Ionization of deep Te donor in Te-doped Al0.6Ga0.4Sb epilayers

The temperature dependence of the electron concentration n(T) for a Te-doped AlxGa1−xSb epilayer with x=0.2 or x=0.6 is obtained from Hall-effect measurements. The density ND and energy level ΔED of Te donors are determined by the graphical peak analysis method (i.e., free-carrier concentration spectroscopy) from the n(T). Since the donor level of Te is shallow in Al0.2Ga0.8Sb, the Fermi–Dirac distribution function, which does not include the influence of the excited states of the Te donors, can be applied to determining ND and ΔED. In Al0.6Ga0.4Sb, on the other hand, a proposed distribution function including this influence is elucidated to be necessary to the determination of ND and ΔED, because Te acts as a deep donor. Moreover, the excited states of the Te donors in Al0.6Ga0.4Sb are found to enhance the ionization efficiency of the Te donors at elevated temperatures.

In situ determination of Nd–Fe–B crystallization pathways

In order to understand the effect of solute additions on the crystallization behavior and to directly measure the crystallization pathways, a series of high temperature x-ray diffraction (HTXRD) experiments were performed on rapidly-solidified Nd2Fe14B alloys from room temperature to 1073 K using high-energy synchrotron radiation and a Debye–Scherrer geometry. The relative phase fractions of crystalline and amorphous material and changes in lattice parameters were determined as a function of temperature using Rietveld analysis. The effect of solute additions on the lattice parameters of the Nd2Fe14B unit cell was clearly evident. As-quenched samples measured at room temperature consist of predominantly glassy Nd–Fe–B (up to 90 wt. %), 8–9 wt. % crystalline Nd2Fe14B and the remainder α-Fe. From room temperature up to the Curie temperature (Tc) for Nd2Fe14B, the unit cell volume contracts primarily due to contraction in the basal plane. From 600 K up to the crystallization temperature the thermal expansion is linear with a positive slope. There is a second inflection in the thermal expansion at the crystallization temperature. This inflection is indicative of solute ejection from the devitrified structure while the negative thermal expansion found for T&amp;lt;600 K is a result of spontaneous magnetostriction which reflects the local anisotropies in the Nd2Fe14B structure.

Derivative Spectrophotometric Determination of Nd, Ho and Er in Rare Earth Mixtures with 1-Ethyl-6,8-difluoro-7-(3-methyl-1-piperazinyl)-4-oxo-1,4-dihydro-3-quinoline carboxylic acid

The second derivative spectrophotometric method has been developed as a procedure for the determination of neodymium, holmium and erbium in mixed rare earths. It was found that the 1-ethyl-6, 8-difluoro-7-(3-methyl-1-piperazinyl)-4-oxo-1,4- dihydro-3-quinoline carboxylic acid forms stable complexes with neodymium, holmium and erbium ions in the pH 9.2–10.5 range. In the second derivative spectra the optimum analytical signals for neodymium, holmium and erbium are at 576.2 (+)−574.5 (−)nm, 444.2 (+) −447.8 (−)nm and 516.0 (+) −517.2(−)nm, respectively. Beer’s law is obeyed from 5.0×10−5 M to 2.5×10−4 M of neodymium, holmium and erbium. The quantification limits (10 Sb) were 1.2×10−5 M for Nd, 9.7×10−5 M for Ho and 3.0×10−6 M for Er.

The Nd and Hf isotopic evolution of the mantle through the Archean. results from the Isua supracrustals, West Greenland, and from the Birimian terranes of West Africa

Evidence for early differentiation events in the Earth’s mantle similar to those that demonstrably affected the Moon and Mars seems to be embedded in the existence of largely super-chondritic 143Nd/ 144Nd ratios in the Early Archean terrestrial mantle. Samples from the ca. 3.8 Ga old rocks from the Isua supracrustal belt, Greenland, and from the ca. 2.1 Ga old juvenile segment of Birimian crust, West Africa, were measured for Nd and Hf isotopic compositions in order to evaluate whether Hf systematics may help enlighten this debate. The determination of Nd and Hf initial isotopic compositions of these terranes is entangled with the uncertainty of which geological events isochron ages and ion probe zircon U-Pb ages actually record, and by metasomatic fractionation of parent/daughter element ratios. It is shown that Nd and Hf mobility has affected the samples for which the Sm/Nd and Lu/Hf ratios depart from the range of modern volcanic rocks. The most conspicuous effect is a preferential leaching of Hf—presumably accompanied by Zr—from mafic metavolcanic rocks. Precipitation of Zr from metasomatic fluids may explain the significantly younger overgrowth zones on zircons from the felsic rocks. For Isua, the pooled whole-rock isochron ages are 3.712 ± 26 Ga (Nd) and 3.593 ± 15 Ga (Hf), while for the Birimian the respective ages are 2.135 ± 29 Ga (Nd) and 2.093 ± 16 Ga (Hf). Elemental mobility and the unsupported assumption of minimum variance underlying the isochron model, however, render the significance of these ages questionable. In an attempt to restore possible ancient mantle-crust arrays, the trajectory of each sample in the (ε Nd[T], ε Hf[T]) space for variable values of the age T are reconstructed. Our best estimate for the isotopic properties of the mantle protolith is ε Nd[3.85] ≈ +2 ± 2 and ε Hf[3.85] ≈ +4 ± 2 for Isua and ε Nd[2.15] ≈ +3 ± 1 and ε Hf[2.15] ≈ +6 ± 2 for the Birimian. We therefore agree with the earlier suggestion that some samples from the Isua supracrustal belt were extracted from a mantle that went through strong parent/daughter fractionation very early in the Earth’s history. This event may be the original differentiation of a largely molten mantle in the presence of majorite garnet. In addition, the contrast between the isotopically inferred long-term Lu/Hf fractionation and the actual Lu/Hf ratio of the rocks requires that garnet was present as a residual mineral (the ‘Hf paradox’). It indicates that melting must have started in the Archean in plumes at a very deep level, thereby providing a mechanism to create thick buoyant oceanic plateaux that would act as nuclei for proto-continents.

Simultaneous determination of neodymium and samarium in silicate rocks and minerals by isotope dilution inductively coupled plasma mass spectrometry: Results on twenty geochemical reference samples

A series of experiments was performed to test the feasibility and the advantages of the determination of Nd and Sm in igneous rocks and minerals by isotope dilution (ID) carried out by inductively coupled plasma quadrupole mass spectrometry (ICP-MS). The main advantage of this method, compared to isotope dilution analyses using thermal ionization mass spectrometers (TIMS), is the high sample throughput. This mainly arises 1. (i) from the direct measurement of the solutions obtained from the acid attack on rock powders using a HF + HNO 3 mixture without any chemical separation procedure, 2. (ii) from the sampling of rock solutions at atmospheric pressure and 3. (iii) from the short time of analysis (about 10 min/sample). In comparison with conventional ICP-MS, the proposed method, is less sensitive to all the possible causes of signal drift and does not need matrix-matched standards. Results obtained for international and in-house igneous rock standards, in a very wide range of Nd and Sm concentrations and Sm Nd ratios, compared also with TIMS/ID and ICP-MS data, indicate an accuracy generally better than 5% and a precision about one order of magnitude better than external calibration ICP-MS.

Determination of lanthanides and actinides in uranium materials by high-performance liquid chromatography with inductively coupled plasma mass spectrometric detection

The determination of Nd, U and Pu by isotope dilution analysis is well known as the classical method for the calculation of the burn-up of a nuclear fuel. Numerous isobaric overlaps restrict the direct determination of fission product and actinide isotopes by mass spectrometry and therefore an extensive chemical separation is required. As a first step towards the development of a more advanced method for the determination of fission product isotopes in irradiated uranium fuel, high-performance liquid chromatographic (HPLC) and inductively coupled plasma mass spectrometric (ICP-MS) systems were installed in glove-boxes and all the lanthanides were separated by HPLC and detected on-line by ICP-MS. As high U and Pu concentrations strongly suppress the signals of trace elements in ICP-MS, a separation method to elute U and Pu first was developed. Thus it was possible to determine the isotopic composition of Nd in a high U and Pu matrix. With the same equipment, a method was developed to prevent isobaric overlaps in the mass spectrum by separating U, Am and Pu.

Extraction and spectrophotometric determination of Nd(III), Th(IV) and U(VI) in synthetic brine using Chlorophosphonazo III

A simple method has been developed to determine micromolar concentrations of Nd(III), Th(IV) and U(VI) in brine. The method involves the extractive separation of these cations from brine matrix species by using Chlorophosphonazo III as extractant with 1-butanol as solvent, and the spectrophotometric determination of the concentration of extracted species in the butanol phase. The lowest concentrations that could be determined are estimated to be 5 × 10−7 M for Nd(III) and 2 × 10−7 M for TH(IV) and U(VI).