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1.
I. E. De Vito R. A. Olsina A. N. Masi 《Fresenius' Journal of Analytical Chemistry》2000,368(4):392-396
A preconcentration method for subsequent determination of rare earth elements (REE) by X-ray fluorescence (XRF) spectrometry
was developed. The method is based on using (o-[3,6-disulfo-2-hydroxy-1-naphthylazo]-benzenearsonic acid) (Thorin) as a complexing
agent which is retained on a polyamide membrane by a chemofiltration process. The pH dependence of the chemofiltration of
these metal ions on the membrane and other variables, such as flow-rate, contact time, kinetic of complex formation, etc.
were determined. The membrane containing the chemofiltrate formed a thin film, which eliminated the interelemental effects
when measured by XRF. The detection limits were 23, 23 and 49 ng/mL for Sm(III), Eu(III) and Gd(III), respectively. High enrichment
factors were obtained. The method was successfully applied to the preconcentration of Sm(III), Eu(III) and Gd(III) from different
samples.
Received: 8 March 2000 / Revised: 9 May 2000 / Accepted: 15 May 2000 相似文献
2.
A very stable chelating resin was prepared by adsorption of (o-[3,6-disulfo-2-hidroxy-1-naphthylazo]-benzenearsonic acid) (thorin) on a macroporous resin Amberlite XAD-7. The optimal conditions for preparing it were obtained through the study of the adsorption properties of the resin and the thermodynamic quantities of the adsorption processes. Likewise, the behavior of the loaded resin with the rare earth elements (REE) were studied (pH of retention, sorption kinetics, etc). The conditions to prepare a thin film with this system were also evaluated. The loaded resin was successfully used for the separation and preconcentration of Sm(III), Eu(III) and Gd(III) prior to their determination by X-ray fluorescence (XRF) spectrometry. The preconcentration factor obtained was 500 and the concentrations at low detection limit were 13.8, 17 and 15.7 microg l(-1) for Sm, Eu and Gd, respectively. 相似文献
3.
M. H. Mallah F. Shemirani M. Ghannadi Maragheh 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):97-102
A new preconcetration method of dispersive liquid-liquid microextraction (DLLME) was developed for simultaneous preconcentration
of samarium, europium, gadolinium and dysprosium. DLLME technique was successfully used as a sample preparation method. In
this preconcentration method, an appropriate mixture of extraction solvent, disperser solvent was injected rapidly into an
aqueous solution containing Sm, Eu, Gd and Dy after complex formation using chelating reagent of the 1-(2-pyridylazo)-2-naphthol
(PAN). After phase separation, 0.5 mL of the settled phase containing enriched analytes was determined by inductively coupled
plasma optical emission spectrometry (ICP-OES). The main factors affected the preconcentration of Sm, Eu, Gd and Dy were extraction
and dispersive solvent type and their volume, extraction time, volume of chelating agent (PAN), centrifuge speed and drying
temperature of the samples. Under the best operating condition simultaneous preconcentration factors of 80, 100, 103 and 78
were obtained for Sm, Eu, Gd and Dy, respectively. 相似文献
4.
A new on-line Gd preconcentration and determination system associated to flow injection (FI) method was developed. 2,2′-(1,8-dihydroxy-3,6-disulfonaphthylene-2,7-bisazo) bisbenzenearsonic acid (Arsenazo III) was used as a complexing agent at pH 2.5. A reactor containing the polyamide membrane was used for the retention of the Gd complex by chemofiltration. The complex was then removed from the reactor with buffer solution pH 9. The variables affecting the combined on-line preconcentration-absorptiometric method have been evaluated and optimised. The coupling of the on-line preconcentration and spectrophotometric flow through detection led to a detection limit of 15 μg l−1 for a preconcentration time of 5 min at 2 ml/min. The method was successfully applied to biological samples. 相似文献
5.
Wu WN Tang N Yan L 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,71(4):1461-1465
Six complexes of rare earth nitrates (Ln=La, Sm, Eu, Gd, Tb, Dy) with a new amide type ligand, N-(naphthalen-2-yl)-N-phenyl-2-(quinolin-8-yloxy)acetamide (L) have been prepared and characterized by elemental analysis, conductivity measurements, IR and and 1H NMR spectra. Under excitation, Eu(III) and Sm(III) complexes exhibited strong red emissions. And the luminescence intensity of Sm(III) complex is higher than that of Eu(III) complex. Thus the Eu(III) and Sm(III) complexes are the potential light conversion agent. However, the Tb(III) and Dy(III) complexes cannot exhibit characteristic emissions of terbium and dysprosium ions, respectively. The results of phosphorescence spectrum show that the triplet-state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. In addition, the luminescence of the Eu(III) complex is also relatively strong in highly diluted tetrahydrofuran solution (2 x 10(-4)mol/L) compared with the powder. This is not only due to the solvate effects but also to the changes of the structure of the Eu(III) complex after being dissolved into the solvents. Furthermore, owing to the co-luminescence effect, the proper La(III) or Gd(III) doped Eu(III) complexes show stronger luminescence than the pure Eu(III) complex. 相似文献
6.
Zaizheng Zhang Jie Zhang Ying Chen Chuanhong Tu Jidian Zheng 《Analytica chimica acta》1997,350(3):365-369
This paper reports the determination of samarium, europium and gadolinium by Sm and Gd monoxide emission and Eu atomic emission. The enhancement effect of other rare earth elements on Sm, Eu and Gd emission was studied. Large amounts of lanthanum (La) were used as enhancing reagents and chemical interference inhibitors and the dual wavelength method was introduced to eliminate spectral interference, in which the analytical wavelengths used were Sm 651.0 nm, Eu 459.4 nm and Gd 461.6 nm and the reference wavelengths were Sm 651.4 nm, Eu 459.8 nm and Gd 461.2 nm. The method has been applied to the assay of Sm, Eu and Gd in synthetic Sm---Eu---Gd concentrates with satisfactory results. 相似文献
7.
研究了稀土元素Sm、Eu、Gd对于Nb掺杂的TiO2基压敏电阻电学性能的影响. 几种稀土元素的掺杂量均为体系总量的2%(原子比), 其它原料的掺入量固定不变. 实验样品在1380 ℃烧结, 保温4 h. 实验发现, Sm、Eu、Gd等稀土元素可以有效降低TiO2基压敏电阻的压敏电压, 但对于非线性系数的影响不很明显. 对于Sm、Eu、Gd掺杂, 实验得到的压敏电压值分别为12.7、14.7和16.1 V. 通过对试样的阻抗分析发现, Sm、Eu、Gd掺杂对于压敏电阻的介电性能有显著影响, 单独掺杂Sm或Gd的试样具有很低的介电常数和介电损耗, 并且具有很高的电阻率. 相似文献
8.
The dissociation constants of 7-iodo-8-quinolinol-5-sulfonic acid and the formation constants of it's chelates with La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III), Yb(III) and Lu(III) have been determined potentiometrically in 1:1 v/v dioxane-water medium at 25±0.1°C and at an ionic strength of 1 with respect to sodium chloride. 相似文献
9.
Mabel Vega Miriam Augusto María C. Talío Liliana P. Fernández 《Microchemical Journal》2011,99(2):425-428
In the present work, a new methodology for zinc preconcentration and separation and its determination by X-ray spectrometry is proposed. The methodology is based on the formation of a complex using Eriochrome black T (1-naphtalensulfonic acid, 3-hidroxy-4-((1-hidroxy-2-naphtalenyl)azo)-7-nitro, monosodium salt), EBT, as complexing agent. Next, the complex is retained on a polyamide membrane by a chemofiltration process. The chemofiltrated material on the membrane constitutes a thin film, which minimizes or eliminates the interelemental effects when the instrumental detection is realized by X-ray fluorescence spectrometry. As the preconcentration method presented is based on the formation of a complex which will interact with the membrane during the chemofiltration, it was necessary first to establish the optimal conditions for the complex formation of Zn-EBT in aqueous medium and then to explore the optimal conditions for obtaining the thin film. The pH dependence of the metal ion chemofiltration on the membrane and other variables, such as contact time and retention capacity of the membrane, were also optimized. Chemofiltration step provided an enrichment factor of 30,000, improving considerably the instrumental detection limit, allowing the determination of trace zinc in environmental samples. 相似文献
10.
Bag P Dutta S Biswas P Maji SK Flörke U Nag K 《Dalton transactions (Cambridge, England : 2003)》2012,41(12):3414-3423
A series of mononuclear lanthanide(III) complexes [Ln(LH(2))(H(2)O)(3)Cl](ClO(4))(2) (Ln = La, Nd, Sm, Eu, Gd, Tb, Lu) of the tetraiminodiphenolate macrocyclic ligand (LH(2)) in 95 : 5 (v/v) methanol-water solution fix atmospheric carbon dioxide to produce the carbonato-bridged trinuclear complexes [{Ln(LH(2))(H(2)O)Cl}(3)(μ(3)-CO(3))](ClO(4))(4)·nH(2)O. Under similar conditions, the mononuclear Y(III) complex forms the dimeric compound [{Y(LH(2))(H(2)O)Cl}(μ(2)-CO(3)){Y(LH(2))(H(2)O)(2)}](ClO(4))(3)·4H(2)O. These complexes have been characterized by their IR and NMR ((1)H, (13)C) spectra. The X-ray crystal structures have been determined for the trinuclear carbonato-bridged compounds of Nd(III), Gd(III) and Tb(III) and the dinuclear compound of Y(III). In all cases, each of the metal centers are 8-coordinate involving two imine nitrogens and two phenolate oxygens of the macrocyclic ligand (LH(2)) whose two other imines are protonated and intramolecularly hydrogen-bonded with the phenolate oxygens. The oxygen atoms of the carbonate anion in the trinuclear complexes are bonded to the metal ions in tris-bidentate μ(3)-η(2):η(2):η(2) fashion, while they are in bis-bidentate μ(2)-η(2):η(2) mode in the Y(III) complex. The magnetic properties of the Gd(III) complex have been studied over the temperature range 2 to 300 K and the magnetic susceptibility data indicate a very weak antiferromagnetic exchange interaction (J = -0.042 cm(-1)) between the Gd(III) centers (S = 7/2) in the metal triangle through the carbonate bridge. The luminescence spectral behaviors of the complexes of Sm(III), Eu(III), and Tb(III) have been studied. The ligand LH(2) acts as a sensitizer for the metal ions in an acetonitrile-toluene glassy matrix (at 77 K) and luminescence intensities of the complexes decrease in the order Eu(3+) > Sm(3+) > Tb(3+). 相似文献
11.
Lanthanum, cerium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, lutetium and yttrium have been determined in 8 international rock standards by inductively coupled plasma atomic emission spectrometry (ICP-AES) without prior ion-exchange separation and preconcentration. The results for La, Ce, Nd, Eu, Dy, Yb and Y were in good agreement with the reported values, whereas those for Sm, Gd, Er and Lu were less accurate. However, the results for Sm, Gd, Er and Lu can also be used for studies of petrogenesis. 相似文献
12.
A. Czylkowska D. Czakis-Sulikowska A. Kaczmarek M. Markiewicz 《Journal of Thermal Analysis and Calorimetry》2011,105(1):331-339
A novel mixed-ligand complexes with empirical formulae: Ln(4-bpy)1.5(CCl3COO)3·nH2O (where Ln(III) = Pr, Sm, Eu, Gd, Tb; n = 1 for Pr, Sm, Eu and n = 3 for Gd, Tb; 4-bpy = 4,4′-bipyridine) were prepared and characterized by chemical, elemental analysis and IR spectroscopy.
Conductivity studies (in methanol, dimethylformamide and dimethylsulfoxide) were also described. All complexes are crystalline.
The way of metal–ligand coordination was discussed. The thermal properties of complexes in the solid state were studied under
non-isothermal conditions in air atmosphere. During heating the complexes decompose via intermediate products to the oxides:
Pr6O11, Ln2O3 (for Sm, Eu, Gd) and Tb4O7. TG-MS system was used to analyze principal volatile thermal decomposition and fragmentation products evolved during pyrolysis
of Pr(III) and Sm(III) compounds in air. 相似文献
13.
Anhydrous lanthanide(III) chlorides (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) react with 3 equiv of lithium 2,2,5,5-tetramethyl-2,5-disila-1-azacyclopentanide, Li[N[Si(CH3)2CH2Ch2Si(CH3)2]], in THF or Et(2)O to afford the monomeric four-coordinate heteroleptic ate complexes Ln[N[Si(CH3)2CH2CH2Si(CH3)2]]3(mu-Cl)Li(THF/Et2O)3 (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7), Tm (8), Yb (9)), whose solid-state structures were determined by the single-crystal X-ray diffraction technique. All complexes additionally were characterized by melting point determination, elemental analyses, and mass spectrometry. 相似文献
14.
Liu M Yuan WB Zhang Q Yan L Yang RD 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(5):1114-1119
A new tripodal, hydroxyl-rich ligand, tris{2-[(3,4-dihydroxybenzylidene)imino]ethyl}amine (L), and its complexes with lanthanide nitrates were synthesized. These complexes which are stable in air with the general formula of [LnL(NO(3))(2)]NO(3).H(2)O (Ln=La, Sm, Eu, Gd, Y) were characterized by molar conductivity, elemental analysis, IR spectra and thermal analysis. The NO(3)(-) groups coordinated to lanthanide mono-dentately, and the coordination number in these complexes may be 8. The interaction of complexes with DNA were investigated by ultraviolet and fluorescent spectra, which showed that the binding mode of complexes with DNA was intercalation, and the binding affinity with DNA were La(III) complex>Sm(III) complex>Eu(III) complex>Gd(III) complex>Y(III) complex. Based on these results, it can be shown that the La(III)complex is promising candidate for therapeutic reagents and DNA probes. 相似文献
15.
《Analytical letters》2012,45(14):2449-2461
Abstract Sorbent extraction and elution of rare earth elements (REEs) by using bis(2‐ethyl‐hexyl)hydrogen phosphate (HDEHP) impregnated porous PTFE filter tube were studied. A 100 ng amount of each REEs was quantitatively extracted by filtering 1000 mL of matrix‐free solution under pH 2.0–3.2. For a synthetic seawater sample, extractability of lighter REEs (La–Sm) was lowered; optimum pH range to simultaneously extract all REEs was shifted to 2.9–3.2, and limit of sample volume for quantitative extraction was decreased to 100 mL for La–Sm [although heavier REEs (Eu–Lu) were quantitatively extracted from 1000 mL]. Extracted REEs were quantitatively eluted by filtering through 5 mL of 10 mol/L?1 hydrochloric acid to the tube. Hence, maximum preconcentration factors were of 200‐ and 20‐fold for Nd–Lu and La–Sm, respectively. Total recovery of 0.5–10 ng of REEs spiked to 300 mL of natural sea salt solution was tested; quantitative recovery (95.9% for Gd–102% for Eu) were obtained for all REEs except La (54.9%). The REEs in the natural sea salt solution were also determined by ICP‐MS after preconcentration with the present method [RSD=16% (La)–1.1% (Yb), n=3]. 相似文献
16.
Kuramochi Y Nakagawa T Yokoo T Yuasa J Kawai T Hasegawa Y 《Dalton transactions (Cambridge, England : 2003)》2012,41(22):6634-6640
We synthesized Eu(III) and Sm(III) complexes with tridentate phosphine oxide ligands, Eu(hfa)(3)(TPPM) and Sm(hfa)(3)(TPPM) (hfa: hexafluoroacetylacetonato, TPPM: tris(diphenylphosphinyl)methane), and we then examined their luminescent properties. In the complexes the Eu(III) and Sm(III) centres were fully surrounded by low-vibrational frequency ligands, which led to relatively high emission quantum yields (Φ(Eu) = 30%, Φ(Sm) = 4.7%). The X-ray single crystal structures of the Eu(hfa)(3)(TPPM) revealed nona-coordinated Eu(III) complexes and C-H/O hydrogen bonding formations between the acidic hydrogen atom of the TPPM ligand and oxygen atoms of solvent molecules. The C-H/O hydrogen bonding slightly affected the coordination structure around the Eu(III) ion. Despite the seemingly small effect on the structural change, because the emission band profile of the (5)D(0)→(7)F(2) transition is sensitive to changes in the coordination environment of the Eu(III) complex, we observed a red shift in the emission spectral line. 相似文献
17.
Farhat Waqar Saida Jan Bashir Mohammad Muhammad Hakim Shah Alam Wasim Yawar 《中国化学会会志》2009,56(2):335-340
An analytical method has been developed for the preconcentration of rare earth elements (REEs) in seawater for their determination by inductively coupled plasma optical emission spectrometry (ICP‐OES). An indigenously synthesized chelating resin was used for the preconcentration of (REEs) which was based on immobilization of fluorinated β‐diketone group on solid support styrene divinyl benzene. Sample solutions (adjusted to optimized pH) were passed through a polyethylene column packed with 250 mg of the resin. Experimental conditions consisting of pH, sample flow rate, sample volume and eluent concentration were optimized. The established method has been applied for the preconcentration of light, medium and heavy REEs in coastal sea water samples for their subsequent determination by (ICP‐OES). Percentage recoveries of La, Ce, Nd, Sm, Eu, Gd, Dy, Er, Yb and Lu were ≥ 95%, a preconcentration factor of 200 times, and relative standard deviations < 5% were achieved. 相似文献
18.
The synthesis, X-ray structure, stability, and photophysical properties of several trivalent lanthanide complexes formed from two differing bis-bidentate ligands incorporating either alkyl or alkyl ether linkages and featuring the 1-hydroxy-2-pyridinone (1,2-HOPO) chelate group in complex with Eu(III), Sm(III), and Gd(III) are reported. The Eu(III) complexes are among some of the best examples, pairing highly efficient emission (Phi tot (Eu) approximately 21.5%) with high stability (pEu approximately 18.6) in aqueous solution, and are excellent candidates for use in biological assays. A comparison of the observed behavior of the complexes with differing backbone linkages shows remarkable similarities, both in stability and photophysical properties. Low temperature photophysical measurements for a Gd(III) complex were also used to gain insight into the electronic structure and were found to agree with corresponding time-dependent density functional theory (TD-DFT) calculations for a model complex. A comparison of the high resolution Eu(III) emission spectra in solution and from single crystals also revealed a more symmetric coordination geometry about the metal ion in solution due to dynamic rotation of the observed solid state structure. 相似文献
19.
André JP Geraldes CF Martins JA Merbach AE Prata MI Santos AC de Lima JJ Tóth E 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(22):5804-5816
The synthesis and characterization of a new class of DOTA (1,4,7,10-tetrakis(carboxymethyl)-1,4,7,10-tetraazacyclododecane) monoamide-linked glycoconjugates (glucose, lactose and galactose) of different valencies (mono, di and tetra) and their Sm(III), Eu(III) and Gd(III) complexes are reported. The 1H NMR spectrum of Eu(III)-DOTALac2 shows the predominance of a single structural isomer of square antiprismatic geometry of the DOTA chelating moiety and fast rotation about the amide bond connected to the targeting glycodendrimer. The in vitro relaxivity of the Gd(III)-glycoconjugates was studied by 1H nuclear magnetic relaxation dispersion (NMRD), yielding parameters close to those reported for other DOTA monoamides. The known recognition of sugars by lectins makes these glycoconjugates good candidates for medical imaging agents (MRI and gamma scintigraphy). 相似文献
20.
Quantitative recovery and preconcentration of trace amounts of Ce(III), Co(III), Eu(III), Fe(III), Gd(III), Mn(II), Y(III) and Zn(II) ions from nearly saturated brines on the chelating resin Chelex-100 are described. Carrier-free radioactive isotopes were used. Only manganese was significantly affected by the high ionic strength of the brines. Chromium (III) was retained quantitatively by the resin but not eluted quantitatively. The results indicate that transition metal and rare earth ions can be quantitatively preconcentrated from solutions of low and high ionic strength. 相似文献