Extraction of europium complexes with 1,2,4,5-benzenetetracarboxylic acid and neutral ligands

Extraction of mixed-ligand europium complexes with 1,2,4,5-benzenetetracarboxylic (pyromellitic) acid and neutral ligands was studied. The complexation of europium with the ligands is discussed on the basis of data on europium distribution in extraction systems, as well as IR and luminescent spectroscopy data of extracts. Crystalline polynuclear europium complexes with pyromellitic acid and 1,10-phenanthroline and tris(hydroxymethyl)aminomethane were isolated from the extracts. The composition of pyrolysis products of extracts was studied. It was shown that nanosized bulk samples of europium oxide can be obtained by the pyrolysis of saturated extracts. Differences in the morphology of europium oxide nanoparticles were revealed in the samples obtained by pyrolysis of extracts differing in composition at the same temperature and time.     

混合价黑色氧化铕的制备及其性质初步研究

用含肼甲酸铕在Ｎ２气氛中热分解的方法制得了混合价黑色氧化铕粉末。对它的有关物理化学性质进行了初步研究,得到了相应的结论。     

铕-速尿-TOPO荧光配合物的研究及速尿的测定

在pH7.8的缓冲溶液中,铕离子、速尿和三辛基氧膦(TOPO)反应生成稳定的三元配合物,该配合物溶解在Triton X-100胶束中。以280 nm光波激发,配合物发射出铕离子的特征荧光。分析了三元配合物的紫外及荧光光谱,对配合物的生成及TOPO和Triton X-100的荧光增敏机理进行了探讨。采用时间分辨荧光法测定配合物的荧光强度,其荧光强度和速尿的浓度在一定范围内呈线性关系,建立了工作曲线的线性回归方程。方法的检出限为6.6×10-8mol/L,测定精度RSD为1.3%(4.00×10-6mol/L,n=11)。用此方法测定尿液中痕量速尿,回收率为93.0%～103%。     

Simultaneous determination of samarium, europium and terbium with quinaldic acid and phenanthroline by synchronous derivative fluorimetry

Synchronous derivative fluorescence of samarium, europium and terbium complexes with quinaldic acid and phenanthroline was examined in aqueous solution. The composition of these complexes was determined. The maximum emission wavelengths are 645 nm, 617 nm and 545 nm for samarium, europium and terbium, respectively. Under the optimal experimental conditions, the fluorescence intensity was a linear function of concentration in the range of 10-250 ppm for samarium, 0.5-50 ppm for europium and 0.5-300 ppm for terbium. Simultaneous determination of samarium, europium and terbium was successfully carried out for samarium oxide and middle rare earth mixture. The precision of the method, expressed as relative standard deviation, is within 1.1-2.5%.     

Extractive chromatographic separation and inductively coupled plasma atomic emission spectrometric determination of trace impurities in high purity europium oxide

An easily applicable separation method has been developed for the accurate and simultaneous determination of trace amounts of Al, Ca, Co, Cr, Cu, Mg, Mn, Ni, Pb and Zn in high purity europium oxide by inductively coupled plasma atomic emission spectrometry (ICP-AES) combined with extraction chromatography. Spectral interferences and europium matrix effects were examined. The chromatographic separation procedure was carried out with a di-(2-ethylhexyl) phosphoric acid (HDEHP)-Levextrel resin as the stationary phase, which retained the matrix europium, and dilute nitric acid as the mobile phase, which eluted the analyte of interest. The effect of nitric acid concentration on the adsorption of europium and the analyte ions on the resin, the eluting behaviour of these elements on the chromatographic column, and the capacity of the resin for europium oxide were investigated. The quantitative limits for determination (10 sigma), based on a 0.5-g amount of europium oxide, are between 0.36 microg/g for Mn and 6.4 microg/g for Pb. The method was applied to two spiked samples and a high purity europium oxide certified reference material. Results were obtained for recoveries of 93.2-112% and precision of 4-13%, expressed as the relative standard deviation and excellent agreement with the certified value with a relative error of <4%.     

Europium Structural Effect on a Borosilicate Glass of Nuclear Interest

Short and middle range order structure of a borosilicate glass of nuclear interest doped with europium oxide was investigated in this study. Neutron diffraction and Wide Angle X-ray Scattering were used as experimental techniques. Furthermore, Reverse Monte Carlo simulation technique was also applied to build reliable atomistic models of the different glasses involved. Simulation results show that europium is more efficiently 6-coordinated in the borosilicate glasses concerned, with a Eu-O distance of 2.31 ű 0.01 Å. Partial pair distribution functions and atom count mainly indicate that europium appears in both silicate and borate environments and that ^IVB/^IIIB ratio decreases with europium oxide increase.     

Partition of Europium(III) with β-diketones and neutral additives between micellar and bulk phases in aqueous nonionic surfactant solutions

The dstribution ratio of europium(III) with a β-diketone and a neutral adduct between micellar and bulk phases in aqueous nonionic surfactant solution was measured by a spectrofluorimetric method as a function of hydrogen ion concentration. The synergic effect of trioctylphosphine oxide for the various β-diketone chelates is much greater than that of tributyl phosphate.     

Thermodynamics of the solvent extraction of thorium and europium nitrates by neutral phosphorylated ligands

Solvent extraction of tetravalent thorium and trivalent europium ions from nitrate media into dichloromethane solution of triphenylphosphine oxide (TPPO) has been studied. The extractant was shown to be more efficient for europium than for thorium. A conventional log-log analysis reveals that the extraction of both metal nitrates takes place via the formation of the species with 1 : 2 metal to ligand ratio. Thermodynamic parameters i.e., ΔG°, ΔH° and ΔS° of the extraction process using 1,2-dichloroethane as diluent have been calculated based on the influence of the temperature on extraction equilibria in the range 293-313 K. While the extraction of europium is controlled by enthalpy changes, the extraction of thorium is an endothermic process and is driven by entropy changes. A comparison of these data with those obtained for the extraction of europium and thorium nitrates by two other related phosphorylated ligands, tri-n-octylphosphine oxide (TOPO) and diphenyl-N,N-dimethylcarbamoylmethylphosphine oxide (DФDMCMPO), indicates that DФDMCMPO coordinates presumably as a chelating ligand. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermochemical synthesis of luminescent materials in the Y<Subscript>2</Subscript>O<Subscript>3</Subscript>–ZnO system doped with Eu<Superscript>3+</Superscript> ions

Powders were synthesized in the yttrium oxide + zinc oxide system doped with europium oxide by the method of redox combustion of a mixture of yttrium, zinc, and europium nitrates in the presence of saccharose (fuel). The structure and the physicochemical and luminescent properties of the particles being formed and of a ceramic on their basis were examined.     

Neutron activation analysis of rare earth impurities in europium oxide

A neutron activation analysis method for determining Yb, Dy, Ho, Sm and La impurities in europium oxide with sensitivities of 10^?5 to 10^?7% is described. The method is based on a preliminary concentration of the rare earth elements by reducing europium(III) with zinc to europium(II), and separating the trivalent rare earth elements by extraction chromatography. After neutron irradiation, the individual radioisotopes of the rare earth elements are separated by using KU-2 cation exchange resin and ammonium α-hydroxyisobutyrate solution as the eluant.     

ENHANCEMENT OF ENERGY TRANSFER FROM THE TERMINAL CHROMOPHORE OF POLYETHER TO EUROPIUM CATION(Ⅲ)VIA COMPLEXATION

The fluorescence spectra of naphthalene end-labelled polyethylene glycol)(N-P_nN) in methanol solution in the presence of europium cation(Ⅲ) was investigated. Selective excitation of the naphthalene group of N-P_n-N re-sults in the emission of europium cation. suggesting that the polyether chain complexes with europium cation, thus efficient energy transfer from naphthalene chromophore to europium cation occurs. Photoirradiation of N-P-N in solution leads to intramolecular dimerization of the two terminal naphthalene groups to give a crown ether. The complexation of this photochemically synthesized crown ether and europium cation was also studied.     

Spectrophotofluorimetric determination of terbium, europium and samarium with pivaloyltrifluoroacetone and tri-n-octylphosphine oxide in micellar solution of nona-oxyethylene dodecyl ether

The fluorescence intensities of terbium, europium and samarium complexes with several beta-diketone derivatives in the absence and presence of tri-n-octylphosphine oxide (TOPO) in micellar solution of nona-oxyethylene dodecyl ether (BL-9EX) were examined. The spectrophotofluorimetric determination of terbium (1.5-1500 ng/ml) has been investigated with pivaloyltrifluoroacetone (PTA) and TOPO in 0.5% micellar solution (pH 3.8-4.5) of BL-9EX. The excitation and emission wavelengths were 309 and 542 nm, respectively. Europium and samarium could be determined by a similar method.     

铕-N,N-二(N-亚甲基琥珀酰亚胺)甘氨酸-1,10-二氮杂菲三元配合物的光致变色

合成了N,N-二(N-亚甲基琥珀酰亚胺)甘氨酸,并以元素分析、IR、¹HNMR和质谱进行表征.实验中发现铕(Ⅲ)与N,N-二(N-亚甲基琥珀酰亚胺)甘氨酸和1,10-二氮杂菲形成的配合物具有光致变色的性质.在铕变色物种里,铕离子与N,N-二(N-亚甲基琥珀酰亚胺)甘氨酸中的羧基,1,10-二氮杂菲中的氮原子相结合,同时也可能与水分子和羟基基团结合.     

Spectrofluorimetric determination of europium and samarium with mixtures of 2-thenoyltrifluoroacetone and tri-n-octylphosphine oxide in aqueous solutions containing triton x-100

The europium or samarium complex with thenoyltrifluoroacetone and tri-n-octylphosphine oxide in aqueous 0.2% Triton X-100 solution at pH 3.6 is used to determine europium (1.5–760 ng ml^-1) or samarium (15–1500 ng ml^-1). The excitation wavelength is 352 or 372 nm; the emission wavelength is 613 or 561 nm. The procedures give better sensitivity than the corresponding extraction methods. A standard addition method is used to overcome interferences.     

Investigation of ion adsorption on silver sulfide,iodide and bromide precipitates by the radioactive tracer technique

The radioactive tracer method was used to investigate the adsorption of iodide and europium ions from aqueous solution on dried isoelectric precipitates of silver sulfide, silver iodide and silver bromide. The relationship between the amount of iodide ions adsorbed on Ag₂S and the iodide ion and HNO₃ concentrations in the solution was determined. It was shown that the iodide ions adsorbed on Ag₂S could be desorbed with sulfide ions. Using Ag₂S, AgI and AgBr precipitates, a relationship between the europium ion adsorption and Eu(NO₃)₃, H₂S, NaI, NaBr and NaCl concentration in solution was established. The adsorption of europium ions was also assessed in respect to the presence of lanthanum and barium ions. For adsorption measurement iodide and europium ions were labeled with their radioactive isotopes and the amounts adsorbed were determined from the measured radioactivities of the precipitates after reaching the equilibrium between the solid phase and the solution.     

稀土配合物的时间分辨光谱分析法研究(Ⅰ)TFA-TOPO-农乳-100体系用于测定铕和钐

本文采用自己组装的时间分辨荧光光谱测定装置,研究了铕(钐)-三氟乙酰丙酮-三正辛基膦化氧(Eu(Sm)-TFA-TOPO)在非离子表面活性剂农乳-100存在下的光谱特性、荧光衰减动力学特性和发光机理。提出了能量传递机制和第二配体TOPO在荧光发射过程中的作用,制定出TFA-TOPO-农乳-100体系测定痕量铕和钐的时间分辨荧光光谱分析方法,用于测定高纯氧化钇中的痕量铕和钐,结果令人满意。     

Highly sensitive spectrofluorometry of europium(III) as its benzoyltrifluoroacetone complex with trioctylphosphine oxide by means of solvent extraction and vacuum sublimation

Summary A new method for the highly sensitive fluorometric determination of europium(III) as its benzoyltrifluoroacetone (BFA) complex with trioctylphosphine oxide (TOPO) without uncombined BFA in n-hexane has been established by means of solvent extraction and vacuum sublimation. The effect of various factors on the fluorescence intensity of europium(III) was investigated. The fluorescence intensity was measured at 620 nm against rhodamine B as an internal standard under the excitation at 335 nm. It was found that a heating treatment gave rise to the enhancement of the fluorescence intensity for about twice times compared with that without heating treatment. Excellent linearity of the calibration curve of europium(III) was obtained in the range of 0–100 ppb. A few ppb of europium(III) can still be detected with this method. All 13 rare earth metals and cobalt(II) tested gave a somewhat positive error. Aluminium(III), iron(III), and copper(II) caused a negative error. The interference of aluminium(III) and iron(III) was removed by extraction with 0.1 mol/l 8-quinolinol in chloroform at pH 4.0, while the problem of cobalt(II) and copper(II) was solved by masking with 0.1 mol/l Na₂S₂O₃ in aqueous solution.

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Hochempfindliche spektrofluorimetrische Bestimmung von Europium(III) als Benzoyltrifluoracetonkomplex mit Trioctylphosphinoxid mit Hilfe der Lösungsextraktion und Vakuumsublimation

     

Voltammetric determination of meclizine HCL and its application in pharmaceuticals and biological fluid using CNTS/ZnO nano-carbon modified electrode

In this article, we report a methodology for the voltammetric behavior of meclizine hydrochloride at different nano modified electrodes e.g., Glassy carbon (GCE), pencil graphite (PGE), Carbon Nano tubes-carbon paste (CNTS-CPE) and Carbon Nano tubes-zinc oxide carbon paste (CNTS/ZnO-CPE) using cyclic and square wave voltammetry and the highest performance of them was CPE/CNTs/ZnO electrode and therefore was used as working electrode. The oxidation reaction mechanism of meclizine hydrochloride (MEC-HCL) is proposed to be one electron system. The results obtained with a square wave were linear over the concentration ranges 19.5–102.4 ng mL^?1 with a correlation coefficient 0.998. The square wave technique showed a low of detectable (LOD) of 6.444 ng/mL and a limit of quantification (LOQ) of 19.530 ng/mL at CNTS/ZnO-CPE. Based on these findings, a simple and not time-consuming method was used for the analysis of MEC-HCL in pharmaceutics and biological fluids. The method showed a minimum detectability (LOD) of 0.02, 0.008 and 0.14 lg/mL and a limit of quantitation (LOQ) of 0.06, 0.02 and 0.42 lg/mL at PGE, CPE and GCE, respectively. The method was validated and compared with the reference valid method. It revealed good accuracy and reproducible results. The anticipated voltammetric procedure has the advantage of being simple, precise, inexpensive and highly sensitive.     

Selective accumulation of light or heavy rare earth elements using gram-positive bacteria

The accumulation of samarium from a solution only containing samarium by Arthrobacter nicotianae was examined. The amount of accumulated samarium was strongly affected by the concentration of samarium and pH of the solution. The accumulation of samarium by the strain was very rapid and reached equilibrium within 3 h. The accumulation of samarium-europium or europium-gadolinium from the solution containing the two metals using various actinomycetes and gram-positive bacteria was also examined. Most of the tested strains could accumulate similar amounts of samarium and europium; however, most of the tested strains could accumulate a greater amount of europium than gadolinium. Especially, the amounts of accumulated europium using gram-positive bacteria were higher than those using actinomycetes. The selective accumulations of light or heavy rare earth elements (REEs) using A. nicotianae and Streptomyces albus were also examined. The amounts of accumulated samarium and europium were higher than those of the other light REEs using both microorganisms. S. albus can accumulate greater lutetium than other REEs from a solution containing yttrium and eight heavy REEs. On the other hand, A. nicotianae can accumulate higher amounts of terbium and ytterbium than that of the other heavy REEs from the same solution. A. nicotianae can also accumulated higher amounts of Sm than other REEs from a solution containing six light REEs.     

Europium oxide containing catalysts for oxidative dehydrogenation of alkanes

A method is developed to incorporate europium into Mg–Al hydrotalcites, which are precursors for oxide catalysts of oxidative dehydrogenation (ODH) of alkanes; samples of oxide catalysts are prepared, where europium oxide and gallium, magnesium, aluminum, chromium, vanadium, molybdenum, and niobium oxides are contained in various combinations. The catalytic properties of these catalysts in the reactions of ethane, propane, and butane ODH are studied. The incorporation of europium into some of our studied multicomponent catalysts enhances the reaction selectivity and increases yields of desired products.