共查询到20条相似文献,搜索用时 15 毫秒
1.
I. P. Alimarin A. Z. Miklishanskii Yu. V. Yakovlev 《Journal of Radioanalytical and Nuclear Chemistry》1970,4(1):45-51
A method with a sensitivity of 2·10−7 to 1·10−10% has been developed for determining Yb, Ho, Dy, Gd, Eu, Sm and La impurities in metallic uranium by means of neutron activation.
The method is based on a preliminary chromatographic separation of the total amount of rare earth elements from uranium by
passing the solution in sulphuric acid through KU-2 cation exchange resin and eluting the traces of uranium retained by the
resin with a solution of ascorbic acid. The rare earth impurities are then eluted from the resin with 4–5N HCl, evaporated, and irradiated for 20 hours with a neutron flux of 1.2·1013 n·cm−2·sec−1. Subsequently the traces of the rare earth elements are co-precipitated with Fe(OH)3, dissolved in concentrated HCl and separated from the iron and other impurities by passing the solution through Dowex 1X8
anion exchange resin in the chloride form. The individual rare earth elements are then separated from each other using KU-2
cation exchange resin and a solution of ammonium α-hydroxyisobutyrate as the eluant. 相似文献
2.
H. Bruchertseifer Choi Valsek K. A. Gavrilov M. Schwarzenberg 《Journal of Radioanalytical and Nuclear Chemistry》1983,77(1):97-104
The electrolytic deposition of the hydroxides of rare earth and transplutonium elements on nickel holders from α-hydroxyisobutyrate
solutions of 10−5 M to 5·10−1 M concentrations has been investigated in the presence of ammonium chloride. It is shown that at total concentrations of
≥10−12 M of rare earth and transplutonium elements, their electrodeposition proceeds with a 90% yield. 相似文献
3.
I. P. Alimarin Yu. V. Jakovlev A. Z. Miklishansky N. N. Dogadkin O. V. Stepanets 《Journal of Radioanalytical and Nuclear Chemistry》1968,1(2):139-145
Radioactivation analysis is the only method which allows the determination of individual rare earth element impurities in
rare earth elements of high purity. The determination of dysprosium, europium, samarium and gadolinium in yttrium oxide is
complicated by the short half-life of165Dy (138 min.) and by the difficulty of separating traces of these elements from the matrix. A chromatographic method has been
developed, for the separation of traces of Dy, Eu, Sm and Gd from ytrium, on a column packed with anion exchangerAV-17, by means of elution with 0.1N and 0.3M solutions of EDTA-sodium salt, followed by the separation of the mixture of the rare earth impurities on a microcolumn of
cation exchangerKU-2, using a 0.17M solution of ammonium α-hydroxyisobutyrate as the eluent. The sensitivity of the determination of Dy, in the case of irradiating
10 mg of Y2O3 with a flux of 1.2·1013 n·cm−2·sec−1 for 5 min. was 1·10−7%; the corresponding values for Sm, Eu and Gd, when irradiating a 100 mg sample of Y2O3 for 20 hours with the same flux, were 2·10−7%, 1·10−8% and 5·10−6%, respectively. 相似文献
4.
A new method for the determination of trace amounts of 14 rare earth elements in high purity Y2O3 using fluorination assisted electrothermal vaporization inductively coupled plasma atomic emission spectrometry with slurry
sampling was developed. A polytetrafluoroethylene (PTFE) emulsion was used as a fluorinating reagent to promote the vaporization
of the analytes from graphite furnace. The main factors affecting analytical signals were investigated systematically. The
interference of matrix could be minimized in the presence of PTFE. Under optimum conditions, the detection limits for rare
earth elements were 0.032 ng∼2.52 ng and the relative standard deviations were in the range of 1.4% to 4.3%. The proposed
method was applied to the direct analysis of high purity Y2O3 powder with satisfactory results.
Received: 19 June 1999 / Revised: 10 December 1999 / Accepted: 16 December 1999 相似文献
5.
《Spectrochimica Acta Part B: Atomic Spectroscopy》2005,60(9-10):1342-1348
A method for the direct determination of trace rare earth elements in ancient porcelain samples by slurry sampling fluorinating electrothermal vaporization inductively coupled plasma mass spectrometry was developed with the use of polytetrafluoroethylene as fluorinating reagent. It was found that Si, as a main matrix element in ancient porcelain sample, could be mostly removed at the ashing temperature of 1200 °C without considerable losses of the analytes. However, the chemical composition of ancient porcelain sample is very complicated, which makes the influences resulting from other matrix elements not be ignored. Therefore, the matrix effect of ancient porcelain sample was also investigated, and it was found that the matrix effect is obvious when the matrix concentration was larger than 0.8 g l− 1. The study results of particle size effect indicated that when the sample particle size was less than 0.057 mm, the particle size effect is negligible. Under the optimized operation conditions, the detection limits for rare earth elements by fluorinating electrothermal vaporization inductively coupled plasma mass spectrometry were 0.7 ng g− 1 (Eu)–33.3 ng g− 1(Nd) with the precisions of 4.1% (Yb)–10% (La) (c = 1 μg l− 1, n = 9). The proposed method was used to directly determine the trace rare earth elements in ancient porcelain samples produced in different dynasty (Sui, Ming and Qing), and the analytical results are satisfactory. 相似文献
6.
Guo-long Guo Ming-biao Luo Jing-jing Xu Teng-xiang Wang Rong Hua Yu-zhen Sun 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(3):647-651
A method for continuous determination of the light rare earth elements (LREEs) and thorium in Baotou Iron Ore was established.
The light rare earths and thorium were adsorbed on a micro-column packed with HD-8 cation exchange resins. The light rare
earth elements were eluted with 4 mol L−1 HCl–2 mol L−1 NH4Cl solution and determined with tribromo-arsenzao by a 721-E spectrophotometry at 630 nm; thorium was eluted with 5% potassium
oxalate solution and determined with Arsenazo III by a 721-E spectrophotometry at 660 nm. The measured values by the proposed
method were in close agreement with the certified values (Baotou main ore standard sample, Baotou ore R-715 standard sample
and GSD-2 standard sample). The RSD of the light rare earths and thorium in Baotou Iron Ore were of <1.70% and <1.99%, respectively. 相似文献
7.
A novel procedure was developed for the determination of trace cerium on the basis of anodic adsorption voltammetry of the
Ce(III)–alizarin complexon (ALC) complex at a carbon paste electrode (CPE). The procedure is convenient to determine cerium
individually in the presence of other rare earths because there is a 100 mV difference between the peak potentials of Ce(III)–ALC
and other rare earth(III)–ALC complexes in a supporting electrolyte of 0.08 M HAc–NaAc and 0.012 M potassium biphthalate (pH
4.7) when performing linear-scanning from −0.2 to 0.8 V (vs. SCE) at 100 mV/s. The second-order derivative peak currents are directly proportional to the Ce(III) concentration over
a range of 6.0 × 10−9–3.0 × 10−7 M. The detection limit is as low as 2.0 × 10−9 M (S/N = 3) for a 120 s preconcentration. An RSD of 3.5% was obtained for 15 determinations of Ce(III) at a concentration of 4.0
× 10−8 M on the same CPE surface. The method was applied successfully to the determination of cerium in samples of rare earth nodular
graphite cast iron. 相似文献
8.
Jinzhang Gao Yingying Zhang Jie Ren Ming Li Wu Yang 《Central European Journal of Chemistry》2010,8(3):602-606
A sensitive and convenient method for the determination of trace europium ions using an oscillating chemical reaction involving
Ce(IV) - KBrO3 - acetone - oxalic acid - H2SO4 was proposed. The results indicated that the changes in oscillating period (T) was linearly proportional to the negative
logarithmic concentration of Eu3+ (-log C) in the range of 1.41 × 10−8 ˜ 1.41 × 10−4 mol L−1 (r = 0.9982) with a detection limit of 1.04 × 10−9 mol L−1. The recoveries were limited to the range of 99.5% to 100.8%. Under the same conditions, other rare earth ions did not interfere
with the determination of Eu3+. In addition, a perturbation mechanism was also discussed briefly.
相似文献
9.
O. Isildak 《Journal of Analytical Chemistry》2009,64(12):1242-1246
A simple method for determination of common inorganic anions in mushroom samples has been developed by using suppressed ion
chromatography with a pH detection unit. The detection unit which was constructed in such a way that practically no additional
dispersion occurred consisted of a flow-through quinhydrone pH sensor and a small reference electrode. Chromatographic separation
was performed in the order F−, Cl−, NO2−, Br−, PO43−, ClO3−, NO3−, and SO42−, at room temperature by using Ion Pac AS 9-HC anion exchange column. Anion extracts from dried mushroom samples at room temperature
were homogenized and filtered before injection. Under optimized analytical conditions, the detection limits of the method
were between 2 × 10−6 and 3 × 10−4 M, depending on the anion studied. The results showed that the concentrations of fluoride and bromide in all mushroom samples
were below their limit of detection. Nitrite was found to be the lowest abundant ion, while the most abundant ion was sulfate
in all the mushroom samples studied. 相似文献
10.
Determination of Aldehydes and Ketones in Fuel Ethanol by High-Performance Liquid Chromatography with Electrochemical Detection 总被引:1,自引:0,他引:1
A. A. Saczk L. L. Okumura M. F. de Oliveira M. V. B. Zanoni N. R. Stradiotto 《Chromatographia》2006,63(1-2):45-51
A new methodology was developed for analysis of aldehydes and ketones in fuel ethanol by high-performance liquid chromatography
(HPLC) coupled to electrochemical detection. The electrochemical oxidation of 5-hydroxymethylfurfural, 2-furfuraldehyde, butyraldehyde,
acetone and methyl ethyl ketone derivatized with 2,4-dinitrophenylhydrazine (DNPH) at glassy carbon electrode present a well
defined wave at +0.94 V; +0.99 V; +1.29 V; +1.15 V and +1.18 V, respectively which are the basis for its determination on
electrochemical detector. The carbonyl compounds derivatized were separated by a reverse-phase column under isocratic conditions
with a mobile phase containing a binary mixture of methanol / LiClO4(aq) at a concentration of 1.0 × 10−3 mol L−1 (80:20 v/v) and a flow-rate of 1.1mL min−1 . The optimum potential for the electrochemical detection of aldehydes-DNPH and ketones-DNPH was +1.0 V vs. Ag/AgCl. The
analytical curve of aldehydes-DNPH and ketones-DNPH presented linearity over the range 5.0 to 400.0 ng mL−1, with detection limits of 1.7 to 2.0 ng mL−1 and quantification limits from 5.0 to 6.2 ng mL−1, using injection volume of 20 μL. The proposed methodology was simple, low time-consuming (15 min/analysis) and presented
analytical recovery higher than 95%. 相似文献
11.
A new Schiff base ligand, 3-tryptimino-1-phenyl-butan-1-one (TPB), was synthesized. The fluorescence intensity of its terbium(III)
complex was greatly enhanced by addition of 1,10-phenanthroline to an acetonitrile solution. Spectrofluorimetric determination
of trace amounts of Tb3+ was performed based on this effect. The excitation and emission wavelengths are 293 and 546 nm, respectively. Under optimal
conditions, the fluorescence intensities varied linearly with the concentration of Tb3+ in the range of 2.0 × 10−6 to 7.0 × 10−6 M with a detection limit of 2.4 × 10−9 M. Interference by some rare earth ions is described. This method was applied to the determination of trace amounts of terbium(III)
in a high purity Y2O3 matrix. The mechanism of fluorescence enhancement was also studied. 相似文献
12.
Neutron activation γ-spectrometry is sufficiently sensitive for the determination of traces of rare earth elements but quantitative separation from uranium is essential. The rare earth elements in 0.2 M ammonium carbonate medium are quantitatively retained on Chelex-100, and are quantitatively separated from uranium by recycling the eluate. When 10-g samples are used, neutron activation provides detection limits of 1–20 μg kg?1. Recoveries of rare earths, checked by spiking with radiotracers, are essentially complete. 相似文献
13.
H. Jaskólska L. Rowińska M. Radwan 《Journal of Radioanalytical and Nuclear Chemistry》1971,7(1):29-39
In a search for internal isotopic tracers in metallurgical materials a group of elements has been chosen which can be determined
by the neutron activation method with the higher sensitivity. A method has been developed for the determination of W, As,
Au, La, In, Sc, Re and Ir in metallurgical materials. The separation of the elements was carried out using extraction and
precipitation. The determination of the elements was carried out in samples of chamotte brick and washed ores. The limits
of the determination of the elements are of the order of 10−11 g for Au, 10−10 g for In and La and 10−9 g for As, W, Sc, Re and Ir. The large scatter of the results indicates the inhomogeneity of the materials analyzed. 相似文献
14.
A new Schiff-base ligand [N, N′, N″-Tri- (2,4-dihydroxyacetophenone) – triaminotriethylamine (TDATA)] with a tripodal structure
was synthesized. Its fluorescence intensity with the europium(III) complex was increased about 178-fold in the presence of
sodium acetate (NaAc) and about 126-fold in the presence of sodium phosphate (Na3PO4) solution. After adding the organic solvent dimethylsulfoxide (DMSO) to the above system, which leads to Eu3+ the fluorescence was further enhanced about 12-fold. Spectrofluorimetric determination of trace amounts of Eu3+ based on the phenomenon was performed. The excitation and emission wavelength is 365 nm and 615 nm, respectively. Under optimum
conditions, the fluorescence intensities vary linearly with the concentration of Eu3+ in the range of 4.9 × 10−12–3.2 × 10−6 mol · L−1 with a detection limit of 4.5 × 10−12 mol · L−1 (for the TDATA-NaAc-DMSO system) or 6.2 × 10−11–8.6 × 10−6 mol · L−1 with a detection limit of 6.0 × 10−11 mol · L−1 (for the TDATA-Na3PO4-DMSO system). Interferences of some rare earth metals and other inorganic ions are described. The method is a selective,
sensitive, rapid and simple analytical procedure for the determination of europium(III) in a high purity yttrium oxide and
synthetic sample. The mechanism for the fluorescence enhancement is also discussed. 相似文献
15.
A new method for the determination of trace amounts of 14 rare earth elements in high purity Y2O3 using fluorination assisted electrothermal vaporization inductively coupled plasma atomic emission spectrometry with slurry sampling was developed. A polytetrafluoroethylene (PTFE) emulsion was used as a fluorinating reagent to promote the vaporization of the analytes from graphite furnace. The main factors affecting analytical signals were investigated systematically. The interference of matrix could be minimized in the presence of PTFE. Under optimum conditions, the detection limits for rare earth elements were 0.032 ng~2.52 ng and the relative standard deviations were in the range of 1.4% to 4.3%. The proposed method was applied to the direct analysis of high purity Y2O3 powder with satisfactory results. 相似文献
16.
F. Z. Khiari A. Aksoy A. Sahin 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(3):507-511
Extensive sedimentary phosphate deposits exist in the Sirhan-Turayf basin in northwestern Saudi Arabia containing significant
amounts of uranium, thorium, vanadium and rare earth elements. The determination of the concentration and pattern of distribution
of some of these elements is essential for economic aspects. This study reports the analysis of vanadium in selected phosphate
rock samples from the basin using accelerator-based thermal neutrons activation analysis (TNAA). Samples were irradiated in
a thermal neutron flux of 2.5·106 n·cm−2·s−1. The induced activity was measured with a HP-GMX detector coupled to a PC-based data acquisition and analysis system. The
facility was calibrated using certified standards of vanadium. The minimum detection limit of vanadium was about 1 mg. Three
independent measurements on each sample yielded comparable results indicating the reliability of the technique. The vanadium
concentrations in the samples vary from 23 to 457 ppm.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
Certain elements which are not possible to detect with conventional neutron activation analysis can be measured using thermal
neutron-capture gamma-ray analysis. The use of a curved neutron guide at the High Flux Reactor, Grenoble, with a thermal neutron
flux of 1.5·1010n·cm−2·sec−1 and the advantage of a low-background counting system (Ge(Li) detector) far from the reactor core are described. Experimental
detection limits of a number of elements are given for the low-energy and the high-energy regions. Some applications of the
capture gamma-ray method in the whole energy range are studied and are briefly discussed. 相似文献
18.
《Spectrochimica Acta Part B: Atomic Spectroscopy》2005,60(4):537-541
A novel method for the determination of trace rare earth impurities in ZrO2 powder has been developed based on electrothermal vaporization inductively coupled plasma atomic emission spectrometry. A polytetrafluoroethylene slurry was used as a fluorinating reagent to convert both the matrix (Zr) and the analytes (rare earth elements) into fluorides with different volatilities at a high temperature in a graphite furnace. The more volatile ZrF4 was removed in-situ by selective vaporization prior to the determination of the analytes, removing matrix spectral interferences. Under optimum operating conditions, the absolute detection limits of the analytes varied from 0.04 ng (Yb) to 0.50 ng (Pr) with relative standard deviations less than 5%. The recommended approach has been successfully applied to the determination of trace rare earth impurities (La, Pr, Eu, Gd, Ho and Yb) in ZrO2 powder and the results were in good agreement with those obtained by pneumatic nebulization inductively coupled plasma atomic emission spectrometry after the separation of the matrix using a solvent extraction procedure. 相似文献
19.
I. Golicheff M. Loeuillet Ch. Engelmann 《Journal of Radioanalytical and Nuclear Chemistry》1974,22(1-2):113-129
The experimental device used is described. Excitation functions are given for an angle of observation 150° with respect to
the incident beam. The possibilities of applying these reactions to the measurement of surface lithium and fluorine concentrations
are considered. The detection limits for these two elements are shown to be 5·10−3 μg·cm−2 with protons of energy between 1,350 and 1,500 keV. The method is compared with that based on the detection of prompt γ-rays
from the reactions7Li(p, γ)8Be and19F(p, α γ)16O.
相似文献
20.
A method was developed for the determination of 15 trace elements in tin. High-purity tin samples (99.9999% and 99.999%) as
well as tin of technical quality were analysed. Reactor neutron activation of the tin samples was followed by distillation
of the matrix activities from a HBr−H2SO4 medium and Ge(Li) gamma-ray spectrometry of the distillation residue. The sensitivity of the method is generally high. For
the high-purity samples the detection limits vary from 0.02 ppb (scandium) to 200 ppb (iron) for irradiation of 1 g of tin
for 1 week at a thermal flux of 5·1012n·cm−2. ·sec−1. To decontaminate the surface of the tin samples, pre- and post-irradiation etching procedures were applied. The efficiency
of these etching techniques was studied. 相似文献