Determination of analytes at trace level in uranium matrix by ICP-AES without chemical/physical separation

Determination of trace metallic constituents in nuclear materials e.g. U, Pu, Am, Zr etc. by Atomic Emission Spectroscopy requires the separation of the major matrix without the loss of analytes at trace level. For DC Arc carrier distillation technique, carrier is used to separate the matrix physically according to the volatility of the analytes while appropriate extractant in suitable diluent is used for chemical separation in inductively coupled plasma atomic emission spectroscopy (ICP-AES). In the present study an attempt was made to develop a methodology for the determination of B, Cd, Mg, Zn, Al, Sr and Sc at trace level (up to 0.1 μg/mL) in uranium matrix without any chemical or physical separation. It involves identification of suitable analytical lines of uranium for its ICP-AES determination; study the spectral interference of uranium to choose interference free analytical lines, optimization of instrumental and experimental parameters etc. The method was validated using synthetic samples.     

Estimation of trace impurities in reactor-grade uranium using ICP-AES

Estimation of impurities in reactor grade uranium is important from the point of view of neutron economy. For chemical separation, ion exchange and solvent extraction techniques have been employed although the latter is generally preferred. Amongst various extractants TBP (tri-n-butyl phosphate), TBP-TOPO (tri-n-octyl phosphine oxide), or TOPO only (in CCl(4), xylene, dodecane) is most often used. New reagents like Cyanex-923 (mixture of 4 tri-alkyl phosphine oxides)/TEHP (tri-ethylhexyl phosphoric acid) are also being used. This communication reports chemical separation of uranium by precipitation using 1,2-diaminocyclohexane NNN'N'-tetra acetic acid (CyDTA)/ammonium hydroxide in presence of 1,10-phenanthroline and estimation of impurities in the filtrate by ICP-AES. Quantitative separation of U, a high spectral interferent in plasma and recovery of impurities have been achieved. Recovery of Cd has been improved by using 1,10-phenanthroline. The method is accurate and precise, offering a relative standard deviation ranging from less than 4% (3.8% for Eu at the 10mug g(-1) level) to 12.9% (for Ce at the 2.5 mug g(-1) level) for all the elements studied.     

锆存在时铀中杂质元素的化学分离-ICP-AES法

采用磷酸三丁酯（TBP）－氢化煤油萃取油、过氧化氢掩蔽钛、磷酸氢二铵沉淀锆的方法，用ICP－AES法同时测定了锆存在在时铀中的铁、锰、铜、硅、铝、镍和钛7种杂质元素的含量。当测定范围在100μg/g-1000μg/g时，相对标准偏差＜9．0％，回收率为96％－109％。     

ICP-AES法测定金合金首饰中铱元素分析谱线研究

采用电感藕合等离子体发射光谱法(ICP-AES)对金基体溶液中的Ir进行测试,分析讨论了国家标准GB/T21198.4-2007和美国热电Thermo IRIS Intrepid II型ICP光谱仪推荐的几种Ir谱线在金基体中的干扰问题.综合谱线强度、灵敏度、标准曲线相关系数、光强值、干扰谱线位置等因素,确定212.681 nm是该型ICP光谱仪测定金首饰中Ir元素的最佳谱线.     

ICP-AES法测定钢中Al元素光谱干扰的理论研究

本文研究的是,在众多谱线中选出最佳分析谱线的通用方法,铝元素只是作为一个例子。配制一系列单一元素光谱干扰研究试验溶液,并在所选分析谱线波长处逐一扫描。通过谱线叠加情况识别谱线干扰情况,排除元素干扰、基体干扰、试剂干扰等,最终确定最佳分析谱线为394.40 nm和309.27 nm。此实验方法的精密度(RSD)为0.23%～13.8%,元素检出限分别为0.0023%(394.40 nm)和0.0011%(309.27 nm)。     

Determination of trace level impurities in uranium compounds by ICP-AES after organic extraction

The determination was studied of Al, B, Be, Cd, Ca, Co, Cu, Mg, Mn, Mo, Pb, Si, Sn, V, Cr, Ni, and Fe as trace level impurities in uranium compounds by ICP-AES after extraction of uranium with three different mixtures of di-(2-ethyl-hexyl) phosphate (D2EHP) and tri-(2-ethyl-hexyl)-phosphate (T2EHP) in solvents like toluene, carbon tetrachloride, hexane and cyclohexane. The study was carried out in presence of different concentrations of HCl and HNO₃. A single extraction with D2EHP in cyclohexane using nitric acid as matrix was sufficient to reduce the U₃O₈ concentration from 100 g/l to 100 g/ml. The ICP-AES instrumentation applied, allowed the determination of metal concentrations ten-times lower than those usually found in nuclear grade U₃O₈. To check the efficiency of the extraction and the accuracy of the proposed method, Certified Reference Materials were used in the dissolution and extraction steps. The method described can be used for the determination of trace metals in nuclear grade U₃O₈.     

Determination of trace level impurities in uranium compounds by ICP-AES after organic extraction

The determination was studied of Al, B, Be, Cd, Ca, Co, Cu, Mg, Mn, Mo, Pb, Si, Sn, V, Cr, Ni, and Fe as trace level impurities in uranium compounds by ICP-AES after extraction of uranium with three different mixtures of di-(2-ethyl-hexyl) phosphate (D2EHP) and tri-(2-ethyl-hexyl)-phosphate (T2EHP) in solvents like toluene, carbon tetrachloride, hexane and cyclohexane. The study was carried out in presence of different concentrations of HCl and HNO(3). A single extraction with D2EHP in cyclohexane using nitric acid as matrix was sufficient to reduce the U(3)O(8) concentration from 100 g/l to 100 microg/ml. The ICP-AES instrumentation applied, allowed the determination of metal concentrations ten-times lower than those usually found in nuclear grade U(3)O(8). To check the efficiency of the extraction and the accuracy of the proposed method, Certified Reference Materials were used in the dissolution and extraction steps. The method described can be used for the determination of trace metals in nuclear grade U(3)O(8).     

Separation of uranium from other metals by partition chromatography

Uranium(VI) can be separated quantitatively from most other metal ions by partition chromatography on a silica-gel column. The column is treated with aqueous 6M nitric acid; after sorption of the sample, uranium(VI) is selectively and rapidly eluted by methyl isobutyl ketone. In addition to the separation of macro quantities of metal ions, the method has been used successfully for the isolation of trace amounts of metal ions from uranium(VI).     

ECHELE／CCD感耦等离子体原子发射光谱中信噪比和分析动态范围的研究

ＥＣＨＥＬＥ／ＣＣＤ感耦等离子体原子发射光谱中信噪比和分析动态范围的研究杨原，王小如，应海，覃事栋，万婷，黄本立（厦门大学化学系，厦门，３６１００５）关键词ＣＣＤ模式噪音，ＩＣＰ－ＡＥＳ，ＣＣＤ动态范围扩展电荷感应耦合器件（ＣＣＤ）和中阶梯光栅（ＥＣ...     

The determination of uranium using short-lived fission products by cyclic and other modes of activation analysis

The determination of elemental concentration in biological and environmental samples through the detection of short-lived nuclides has been of considerable interest in the last few years. In this context the relative advantages and disadvantages of cyclic activation analysis (CAA) with respect to single conventional one-shot irradiation and counting sequence (for one sample or replicate samples) and what has been termed pseudo-cyclic activation have been discussed with conflicting interpretations. It is the objective of this study to demonstrate through the irradiation of uranium standards by measurement of short-lived fission products how each mode of activation is best utilised. Application of CAA to the problem, in order to enhance signal-to-noise ratio, must also take into account an increasing dead-time with each cycle and therefore mass fractionation of a given sample and standard are investigated for replicate and pseudo-cyclic activation conditions. The variation of timing parameters in the cyclic mode, as well as irradation in a mixed reactor flux and epi-cadmium neutron flux, produces a set of equations from which half-life can be determined to confirm fission product identification in these complex gamma-ray spectra.     

电感耦合等离子体发射光谱法测定地质样品中钨时对锌的光谱干扰校正

采用硝酸-氢氟酸-高氯酸消解样品,电感耦合等离子体发射光谱法测定地质样品中的钨. 讨论了Zn207.908对W 07.911的光谱干扰,并应用光谱干扰系数校正法(IEC)校正干扰. 结果表明:Zn对W的光谱干扰可以用IEC进行有效的消除,进行光谱校正后的结果明显优于未加校正的试验结果.     

ICP-AES determination of silver after chemical separation from uranium matrix

The separation of silver from a uranium matrix has been carried out using Cyanex-471X (triisobutylphosphine sulphide) in xylene. The effects of various parameters such as the Cyanex-471X concentration, the nitric acid molarity, the contact time and the nitrate ion concentration on the extraction of silver have been studied. The silver metal ion species extracted into the organic phase was found to be Ag(NO₃)·2S (where S is Cyanex-471X). The stripping of silver into an aqueous medium was carried out with 5% NaHSO₃, followed by its determination using ICP-AES.     

ICP-AES法对花生仁和黄豆中元素含量的比较研究

采用ICP-AES法对通辽地区产的花生仁和黄豆中Na、K、Mg、Ca、P、Fe、Cu、Mn、Zn、Sn、AI和Si等元素的含量同时进行测定。回归方程的相关系数为0.9992-0.9998,相应各元素的检出限范围为0.25～97.03μg.L－1之间,回收率和相对标准偏差范围分别为97.04～108.60%之间,RSD为0.69～3.26%之间,该实验建立了简便、快速和稳定的测定花生仁和黄豆中元素含量的方法。结果显示在花生仁和黄豆中P含量非常高,黄豆中Ca、Mg、Fe、Zn和Sn的含量较花生仁中的较高。     

Separation of titanium and uranium from other elements by tannin

Summary Titanium and uranium have been precipitated by tannin in the presence of various other ions, e.g., Fe³⁺, Al³⁺, Cr³⁺, Th⁴⁺, Zr⁴⁺, Bi³⁺, Pb²⁺, (VO)²⁺ and rare earths, which are kept in solution by EDTA. The precipitation was carried out by raising the p_H of the acidic solution containing EDTA and tannin by dilute ammonium hydroxide or hexamine. The p_H of complete precipitation of titanium is 4.0 and above and that of uranium is 6.0 and above.

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Zusammenfassung Titan und Uran werden mit Tannin in Gegenwart verschiedener Fremdionen, die durch ÄDTA in Lösung gehalten werden, gefällt (z.B. in Gegenwart von Fe³⁺, Al³⁺, Cr³⁺, Th⁴⁺, Zr⁴⁺, Bi³⁺, Pb²⁺, (VO)²⁺, Seltenen Erden). Die Fällung wird durchgeführt, indem man die saure Lösung, die ÄDTA und Tannin enthält, mit Ammoniak oder Hexamethylentetramin neutralisiert. Titan wird bei p_H-Werten über 4,0 und Uran bei solchen über 6,0 vollständig ausgefällt.

     

Determination of uranium fission interference factors for INAA

Instrumental neutron activation analysis (INAA) is a very suitable technique for the determination of several elements in different kinds of matrices. However, when the sample contains high uranium concentration this method presents interference problems of uranium fission products. The same radioisotopes used in INAA are formed in uranium fission. Among these radioisotopes are ¹⁴¹Ce, ¹⁴³Ce, ¹⁴⁰La, ⁹⁹Mo, ¹⁴⁷Nd, ¹⁵³Sm and ⁹⁵Zr. The purpose of this study was to evaluate uranium fission interference factors to be used in the INAA of environmental and geological samples containing high levels of U. The obtained interference factors agreed with literature reported values. The results point to the viability of using these experimentally determined interference factors for the correction of uranium fission products.     

A separation method to overcome the interference of calcium on the uranium determination by ICP-ES

The accurate determination of uranium by Inductively Coupled Plasma Emission Spectrometry (ICP-ES) in calcium phosphate matrix suffers from a severe ionization interference due to the high calcium content of the samples. This leads to a signal depression up to 30%. For reliable determinations an extraction method based on anion exchange resin column chromatography is described which separates uranium for the needs in ICP-ES measurements. The results are comparable with results obtained by other determination methods. In addition, reference materials were measured to verify this extraction procedure.     

A separation method to overcome the interference of calcium on the uranium determination by ICP-ES

The accurate determination of uranium by Inductively Coupled Plasma Emission Spectrometry (ICP-ES) in calcium phosphate matrix suffers from a severe ionization interference due to the high calcium content of the samples. This leads to a signal depression up to 30%. For reliable determinations an extraction method based on anion exchange resin column chromatography is described which separates uranium for the needs in ICP-ES measurements. The results are comparable with results obtained by other determination methods. In addition, reference materials were measured to verify this extraction procedure.     

Sorption of uranium and other heavy metals on hydroxyapatite

The immobilization of U^VI and Pb^II from aqueous solutions in a solid phase by interaction with calcium hydroxyapatite has been studied in batch experiments with increasing contact times. The results were compared with those previously found for Cd^II. All these elements are able to be efficiently immobilized by such a method. The sorbed quantities vary in the order Pb>U>Cd. The sorption mechanisms are element dependent. The dominant mechanisms are: dissolutionprecipitation with formation of an amorphous or microcrystalline phase for U, dissolution-precipitation with the formation of two new crystalline phases and with possible incorporation into the initial apatite for Pb, and intracrystalline diffusion and exchange for Cd.     

Recovery of uranium from uranium refining waste water by using immobilized persimmon tannin

Some attempts were made to examine the practical conditions for uranium recovery from uranium refining waste water. The adsorbent was highly effective in recovering uranium. The uranium adsorption was affected by pH, temperature, and uranium concentration of the uranium refining waste water. The adsorbent also recovered uranium effectively in column system. It aquires better mechanical properties and can be used repeatedly in the uranium adsorption-desorption cycles.