Determination of yttrium in xenotime ore by energy dispersive X-ray fluorescence spectrometry

A radioisotope-excited X-ray fluorescence analysis is applied for the determination of yttrium in xenotime ore. An annular¹⁰⁹Cd source is employed for excitation of characteristic K X-rays of yttrium. The dilution method using pure starch as a diluent has been examined. Critical thickness of diluted ore sample has been determined. For the estimation of yttrium concentration in xenotime ore, the scattered radiation technique has been utilized. The validity and precision of the method have also been investigated.     

Determination of trace elements in Syrian medicinal plants and their infusions by energy dispersive X-ray fluorescence and total reflection X-ray fluorescence spectrometry

X-ray fluorescence (XRF) and total-reflection X-ray fluorescence (TXRF) techniques suited well for a multi-element determination of K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr in some Syrian medicinal plant species. The accuracy and the precision of both techniques were verified by analyzing the Standard Reference Materials (SRM) peach-1547 and apple leaves-1515. A good agreement between the measured concentrations of the previously mentioned elements and the certified values were obtained with errors less than 10.7% for TXRF and 15.8% for XRF. The determination of Br was acceptable only by XRF with an error less than 24%. Furthermore, the XRF method showed a very good applicability for the determination of K, Ca, Mn, Fe, Cu, Zn, Rb, Sr, and Br in infusions of different Syrian medicinal plant species, namely anise (Anisum vulgare), licorice root (Glycyrrhiza glabra), and white wormwood (Artemisia herba-alba).     

Determination of rare earth impurities in ytterbium oxide by X-ray fluorescence spectrometry

Summary Determination of Kare Earth Impurities in Ytterbium Oxide by X-ray Fluorescence Spectrometry An X-ray fluorescence spectrometric method for the determination of traces of Ho, Er, Tm, Lu and Y oxides in the concentration range of 0.005–1% in ytterbium oxide is developed. The precision at various concentrations of the standards is given. Intensity corrections for line overlaps have been determined.     

偏振能量色散X射线荧光光谱法测定地质样品中18种元素

利用偏振能量色散X射线荧光光谱仪分析了硅酸盐基体样品. 选取岩石、土壤、水系沉积物等国家一级标准物质, 采用镶边粉末压片方法, 选择Al2O3偏振靶、 Mo、 Co二级靶, 在真空状态下对K、 Ca、 Ti、 Cr、 Mn、 Fe、 Ni、 Cu、 Zn、 Ga、 As、 Rb、 Sr、 Y、 Zr、 Nb、 Ba、 Pb等18种元素进行选择激发和探测, 所有元素的校正选用扩展的康普顿散射校正模型. 各元素的检出限为0.4～10.9 μg/g;除了As元素外, 均达到了1:25万多目标地球化学调查规范的要求. 根据60个地质调查多目标考核样品的分析结果, 采用Rousseau(2001)所提出的相对不确定度计算方法, 对所建立的方法进行了评估.     

Determination of nickel in lateritic ore by various techniques of energy dispersive X-ray fluorescence analysis

Radiometric techniques of determining the nickel content in lateritic ore samples are described. In some of the methods proposed a semiconductor detector and a multichannel pulse height analyzer are required. In another technique simple portable equipment with a proportional counter was used. Calculation methods of correction for matrix effects were applied, in combination with measurements of the fluorescence to scatter ratio and the use of edge filters.     

Determination of trace rare earth elements by X-ray fluorescence spectrometry after preconcentration on a new chelating resin loaded with thorin

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.     

Determination of tungsten in ores by energy dispersive X-ray fluorescence analysis

The possible determination of tungsten in low grade ores from Northern India, Rajasthan State has been explored by energy dispersive X-ray fluorescence analysis /EDXRF/ technique using radioisotope based excitation of W L X-rays and high resolution Si/Li/ detector system. Finely powdered ore has been diluted with optimal quantity of cellulose and converted into pellets to make it suitable for X-ray analysis after homogenization. The experiments have shown the minimum detectable limit of 33 ppm in diluted matrix. The results are compared with the spectrophotometric stannous chloride-thiocyanate method. EDXRF appears to be encouraging for routine and precise analysis of tungsten in low grade ores.     

熔融制样-X射线荧光光谱法测定锆钛矿中主次成分

为准确测定锆、钛及其共伴生有用有害杂质元素含量,采用稀释比1∶20的四硼酸锂-偏硼酸锂混合熔剂,先将样品700℃预氧化7 min,再1 050℃熔融19 min制样,建立了熔融制样-X射线荧光光谱法测定锆钛矿中SiO₂、Al₂O₃、Fe₂O₃、CaO、MgO、MnO、TiO₂、K₂O、Na₂O、P₂O₅、ZrO₂等11种主次成分的分析方法。采用标准样品加入光谱纯的方式配制锆钛矿的标准系列样品解决锆钛矿石标准样品不足的问题。结果表明,各组分的检出限在0.004%～0.13%,各组分测定结果的相对标准偏差(RSD,n=12)在0.060%～2.6%。对实际样品进行测定,测定值与传统方法测定值一致,并具有操作简便,分析周期短的优点,解决了锆钛矿石前处理过程中锆钛易水解,分析周期长的问题,对综合评价锆钛矿资源具有重要意义。     

X射线荧光光谱法测定锡矿石中锡

本文采用向样品中加入硼酸来降低基体效应,加入氧化镧来稳定样品总质量吸收系数,建立固体粉末压片制样-X射线荧光光谱法测定锡矿石中锡含量的方法。通过将标准物质按一定比例混合配制和选取部分自制标样来补充标准物质样品,以解决锡矿石标准物质样品缺乏的问题。实验优化了稀释比,确定了以最佳稀释比为m（矿物质样品）:m（硼酸）：m（氧化镧）=1.0:2.0:0.5。在最优的实验条件下,Sn的荧光强度（kcps）与Sn浓度CSn呈良好的线性关系,R2=0.9989。方法中锡元素的最低检出限为0.005 %,测定范围在0.015 %-4.47 %之间。样品的混合均匀性实验表明各元素测定结果的相对标准偏差（RSD,n=6）在1.0 %-2.64 %之间。对3个不同含量段的物质进行测定来验证方法的准确度和精密度,准确度分别为0.0082-0.0367,均小于0.04,精密度分别为0.39 %-1.18 %,均小于8.0 %,准确度和精密度均符合地质样品分析规范要求。测定值均在误差范围内,各组分测定结果的相对标准偏差（RSD,n=11）在1.20 %以下。粉末压片-X射线荧光光谱法测定锡矿石中锡含量具有分析范围广、分析时间短、重现性好、精度高且操作简单等特点。能应用于地质、环境、材料等领域。     

Preconcentration method for the determination of thorium in natural water by wavelength dispersive X-ray fluorescence spectrometry

The preconcentration of thorium from natural water and its determination directly by wavelength dispersive X-ray fluorescence spectrometry (WDXRF) were attempted. The first step consists of thorium preconcentration from slightly acid solutions on polyurethane foam (PUF) loaded with 2-etilhexylphosphonic acid (EHPA) reagent as solid phase. PUF held up to 50% (w/w) of the reagent and the preconcentration was maximum at the acidity of 0.25 mol^.l^-1 hydrochloric solution. Sorption on PUF had fast kinetics and 4.0 and 10 mg^.l^-1 detection and quantitation limits of thorium were achieved, respectively, as well as a R.S.D. of 4.2% at 21.7 mg^.l^-1. This method was successfully applied to natural water analyses. The results were in good agreement with reference values of water samples at 95% confidence level.     

钕-铁系稀土永磁合金的X射线荧光光谱分析

采用X射线荧光光谱测定Nd—Fe系稀土永磁合金中La,Ce,Pr,Nd,Fe,Co成份。该方法既能克服基体效应又能解决标准样品的制备问题,分析方法简便、快速、准确。对于体系较复杂的Nd—Fe系稀土永磁合金,采用本方法RSD小于2％,方法的加标回收率97％-105．8％之间。     

Determination of rare earth elements by radioisotope induced X-ray emission spectroscopy

A ring-shaped, 10⁹ Bq²⁴¹Am radioisotope source was used for the excitation of K-shell X-rays from rare earth elements (56<Z<64), present in powdered geological material. In order to improve the efficiency of the measurement of these elements in the concentration range down to 10 ppm, the optimum geometry of the system was found. The results obtained are presented and discussed.     

Assessment of the Lake Gendabi salt for trace elements and toxic heavy metals by energy dispersive X-ray fluorescence spectrometry

This study has analyzed samples of salts from Lake Gendabi, located in the northern part of Tanzania for metal contamination using the EDXRF spectrometry. The aim of the study was to assess the suitability of the salt from Lake Gendabi for human consumption. Seventy-five samples of salt were collected from the Lake Gendabi floor and grouped into five grades (G1, G2, G3, G4 and G5) depending on the position of the salt from the lake shore. In addition to Na and Cl, concentrations of 17 more elements were determined in all five grades of salt. These included seven toxic metals which are Al, Ni, Cr, Cd, Pb as well as Th and U which are both toxic and radioactive. The concentrations of all toxic elements found in the samples were higher than their Maximum tolerable limits set by international organizations. As this salt is used in many parts of Tanzania, it is proposed that the salt should be thoroughly purified before entering the market. Further research to include salt samples from other salt production areas in Tanzania is recommended.     

Analysis of trace elements in medicinal plants with energy dispersive X-ray fluorescence

Mankind still depend on traditional herbal medicine for the treatment of various diseases and ailments. This paper discusses the elemental composition and concentration of medicinal plants investigated by energy dispersive X-ray fluorescence. The elements present in medicinal plants are P, Cl, K, Ca, S, Al, Ti, V, Rb, Sr, Zr, Nb, Mo, In, Sn, I and Ce. The physical basis of the used analytical method, the experimental set up and the procedure of sample preparation are presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Total reflection X-ray fluorescence determination of rare earth elements in mineral water

A method is proposed for determination of lanthanum, cerium, praseodymium, neodymium, and samarium in mineral water by means of total-reflection X-ray fluorescence analysis. In this work, the combined technique of preconcentration of rare earth ions is used. This technique consists of coprecipitation of metal hydroxides on the collector (iron (III) hydroxide) and dispersive liquid–liquid microextraction of their complexes with 1-(2-pyridylazo)-2-naphthol by chloroform in the presence of ethanol. The use of the developed hybrid approach allows simultaneous determination of the mentioned metals in mineral water in the range n(10^–2–10¹) μg/L. The results of analysis of Arkhyz and Rychal-Su mineral waters by the proposed extraction–X-ray fluorescent method are confirmed by the literature data, obtained by inductively coupled plasma mass spectrometry.     

Determination of traces of hafnium in zirconium oxide by wavelength dispersive X-ray fluorescence spectrometry

An accurate and precise wavelength dispersive X-ray fluorescence spectrometric method is described for the quantitative analysis of hafnium impurities in zirconium oxide matrix in the range from 6.8 to 1004 g/g, using the HfL₁ line on 8420⁺ XRF Quantometer (ARL) with LiF (220) crystal and scintillation detector. The practical limit of measurement is 6.8 g/g. The precision is between 1 to 6% for higher and lower concentrations of hafnium, whereas accuracy in most cases is <5%.     

Determination of rare earth impurities in cerium dioxide and oxalate by X-ray fluorescence technique

A method for the determination of lathanum, praseodymium, neodymium and samarium oxides in cerium dioxide has been developed. The sample in the oxalate form is mixed with the binding material (boric acid) in the ratio 1∶1 pressed to form a double layer pellet over a boric acid backing pellet and irradiated by X-rays from a tungsten tube. The secondary X-rays are dispersed with a LiF (200) crystal in a Philips PW 1220 semiautomatic X-ray fluorescence spectrometer. The intensity of fluorescent X-rays is measured by a flow proportional counter. The minimum determination limit is 0.01% for lanthanum and samarium oxides and 0.02% for praseodymium and neodymium oxides. The precision at each concentration of the standards and theoretical minimum determination limit for each element have been calculated.     

辉光放电质谱法测定稀土矿中的15种稀土元素

利用高纯铜粉与稀土矿石粉末均匀混合压片制样.混合15种高纯稀土氧化物制样建立标准工作曲线,校正15种稀土元素相对灵敏度因子,再进行定量分析.结果 表明,稀土元素工作曲线的线性方程相关系数R2均大于0.996,相对标准偏差(RSD)小于5％,满足定量分析要求.测定结果与电感耦合等离子体质谱法(ICP-MS)和电感耦合等离...     

单波长激发-能量色散X射线荧光光谱法检测蔬菜中多种重金属元素

为实现蔬菜中多种元素的快速检测,利用单波长激发-能量色散X射线荧光光谱仪（MW-EDXRF）,建立了蔬菜中As、Pb、Cd、Cr、Ni、Cu、Zn、Rb、Mn等元素的快速检测方法。对XRF的激发时间、载样量、样品压片等条件进行了优化,结果显示当累积激发时间达到600 s、载样量为2 g、样品压片15 Mpa保持60 s时,可以实现XRF最优检测性能。在最优条件下,As、Pb、Cd、Cr、Ni、Cu、Zn、Rb、Mn的检出限（LOD）分别为0.07 mg/kg、0.07 mg/kg、0.07 mg/kg、0.32 mg/kg、0.32mg/kg、1.2 mg/kg、0.4 mg/kg、0.08 mg/kg、0.3 mg/kg;对菠菜、葱、胡萝卜、豆角、番茄、姜、空心菜、莲藕、芹菜、蒜等蔬菜样品测定11次的相对标准偏差（RSD）在3%~10%,表明方法具有良好的精密度;测定5种蔬菜基体标准物质的回收率在93%~119%,与微波消解电感耦合等离子体质谱法（ICP-MS）测定结果对比的线性回归系数（R2）>0.99（Cu的R2=0.9838）,表明方法具有良好的检测准确度。同时,该仪器仅有不到10 kg,不需要样品消解处理,检测时间在10 min左右,非常适合蔬菜多种重金属的现场快速筛查。     

Determination of aluminium, scandium and rare earth elements by emission flame spectrometry

Summary Emission spectrometry in nitrous oxide-acetylene flames in combination with a highly resolving double monochromator and sensitive detecting system enables simple, sensitive and selective determinations of aluminium, scandium and all rare earth elements with exception of cerium in complicated matrices. Calibration plots are linear for a large concentration interval ( 100 g·ml^–1), detection limits are in ng · ml^–1 level and RSD does not exceed 3% on the optimal concentration level of the particular element. The determination of Al, Sc, Eu and Yb showed particular advantages as to methods using ICP-spectrometry.

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Bestimmung von Aluminium, Scandium und Seltenen Erden durch Emissions-Flammenspektrometrie

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Dedicated to Prof. Dr. G. Tölg on the occasion of his 60th birthday