Determination of rare earth elements in rice by INAA and ICP-MS

In order to improve the accuracy of reactor neutron activation analysis, flux gradients and spectrum changes in the irradiation capsule have been studied at the Kyoto University Reactor (KUR). The flux and spectrum monitoring samples of Fe, Co, Au, Sb, U and Ni were placed at several positions in a polyethylene irradiation capsule of 24 mm inner diameter and 98 mm length, and were irradiated in a pneumatic irradiation facility (Pn-2). The flux gradients were found to be rather negligible in the vertical (axial) direction while they were considerable in the radial one. The flux gradient was around 5%/cm for thermal neutrons and 10%/cm for epithermal and fast neutrons. The spectrum changes were dependent on the materials (polyethylene and silica) filled in the capsule. Based on these observations, the effect of the flux gradients and spectrum changes on the accuracy of reactor neutron activation analysis was discussed.     

High throughput online sequential extraction of natural rare earth elements and determination by mass spectrometry

At the beginning of rare earth industry,several days are normally required for characterization of rare earth elements(REEs)fractionation in ore samples.Herein,rapid fractionation analysis of 15 REEs and accompanied metal(Fe,Mn,etc.)in ore samples has been achieved within 1 h using ICP-MS with a homemade device for online sequential solvent extraction.As a result,five fractionations for REEs occurrences,i.e.,water soluble,exchangeable,reducible,oxidizable and crystalline,have been identified,offering chemical insights which not only reveal the formation mechanism of REEs ores but also show great implications for guiding the exploitation and separation of REEs.In comparison with conventional methods,the present approach significantly shortened the analysis time(1 h vs.~80 h)and reduced the sample consumption(1.0 mg vs.5.0 g)with high recovery(>95%),providing a useful platform for the rapid quantitative fractionation analysis of REEs in complexed samples such as ore and fossils.     

微波消解-电感耦合等离子体质谱法(ICP-MS)测定板栗中的矿物元素及稀土元素[ ]

采用微波消解前处理方法,结合电感耦合等离子体质谱技术,建立了板栗中钠（Na）、钾（K）、镁（Mg）、锰（Mn）、铁（Fe）、钒（V）、钴（Co）等19种矿物元素及镧（La）、铈（Ce）、镨（Pr）、钕（Nd）、钐（Sm）、铕（Eu）、钆（Gd）、铽（Tb）、镝（Dy）、钬（Ho）、铒（Er）、铥（Tm）、镱（Yb）、镥（Lu）、钇（Y）等15种稀土元素的同时分析测定方法。该方法检出限为0.0027~0.78μg?L-1,相对标准偏差为1.4%~6.3%。通过国家标准物质GBW10019苹果的准确率实验验证,测定结果均在标准证书值范围内。实验结果表明,该方法适用于板栗中矿物元素及稀土元素的同时测定。     

ICP-MS同时测定植物性食品中稀土元素的方法研究

建立了植物性食品中16种稀土杂质(Sc、Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb和Lu)元素的电感耦合等离子体质谱(ICP-MS)的分析方法.考察了基体效应及质谱干扰,应用In内标,有效地补偿基体效应所引起的测量偏差,建立修正公式校正质谱干扰.对照分析了参考标准物质.对所测定元素,校正曲线的相关系数为＞0.9990,方法的检出限低于2.2 pg/g(Sc为95pg/g),回收率为92%～106%,RSD优于3.2%(n=7).     

珍珠中痕量稀土元素的ICP-MS测定及其分布特性

探讨了等离子体质谱(ICP-MS)分析珍珠样品中稀土元素的基体效应及多原子离子干扰,并采用干扰校正因子进行有效的校正,以In-Rh双内标校正体系进行分析信号动态漂移的监控和补偿,建立了珍珠样品中稀土元素的ICP-MS分析方法。方法的定量检出限为0．1～0．5ng／g,RSD≤15％(n=5)。所建立的方法用于标准物质Gui-1、Gui-2、Gui-3及人工养殖珍珠的分析。珍珠中稀土元素的分布与分馏特性与其生长环境密切相关。     

Solvent extraction kinetics of rare earth elements

The kinetics of solid-liquid extraction of rare earth elements (RE) (La, Ce, Sm, Dy and Yb) were studied with 1-(2-pyridylazo)-2-naphthol (PAN) at 60 degrees C using paraffin wax as a diluent. The rate of extraction is first order with respect to metal ion and hydrogen ion in the aqueous phase and second order with respect to the extractant in the organic phase. The rate-determining step is the formation of an [RE(PAN)(2)](+) complex between RE(3+) and PAN in the aqueous phase. The rate constant for the extraction was found to be about 10(11) 1 mol(-1) s(-1). The temperature dependence of extraction rate was determined and the activation parameters were calculated.     

Determination of rare earth elements in Indian kimberlite using inductively coupled plasma mass spectrometer (ICP-MS)

A method has been developed for the analysis of rare earth elements (REEs) in kimberlite samples using inductively coupled plasma mass spectrometer (ICP-MS). The samples were dissolved using sodium peroxide fusion and after appropriate dilutions the solutions were analyzed using ICP-MS. The paper presents the concentration of rare-earth elements as determined by ICP-MS in eight kimberlite samples from Central India. The method was validated using certified reference materials STSD-1 and STSD-2 from Canadian Certified Reference Material Project. The method detection limit of various REEs varies from 0.12 to 1.54?mg?kg^?1. The total REE concentrations range from 418 to 726?mg?kg^?1 and fall within the interval of those reported in the literature for kimberlites. Despite the marked difference in the REE contents, all the analyzed samples show similar REE patterns that resemble those for kimberlites. In order to compare ICP-MS results, the samples were analyzed using instrumental neutron activation analysis which is a reference method for determination of REEs in geological samples.     

微敞开体系石墨消解-电感耦合等离子体质谱（ICP-MS）法测定土壤中16种稀土元素

稀土元素被广泛应用于工业领域和农业生产,稀土矿产长期大量开采和广泛使用导致土壤环境中较多稀土元素累积,对农田系统中各种生物造成毒害,并威胁人类健康,建立一种准确、快速测定土壤中稀土元素的方法,对于摸清土壤中稀土污染状况十分必要。基于本课题组前期建立的微敞开消化体系,通过优化内标元素选择、消解时间、复溶方式等,构建了微敞开体系石墨消解-电感耦合等离子体质谱(ICP-MS)法测定土壤中Sc、Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu 16种稀土元素的方法。实验结果表明,最佳的样品前处理条件为高温消解375 min、消解后加入5 mL 2% HNO3溶液开盖复溶。采用Rh-Re双内标校正能降低基体效应,显著改善稀土元素测定回收率。方法中各稀土元素标准曲线均线性关系良好（R≥0.999）,方法检出限为0.006 ~ 0.02 mg/kg,定量限为0.024 ~ 0.08 mg/kg。按实验方法检测的12个国家土壤标准物质测定值与参考值一致,两个实际土壤样品中各稀土元素测定值的相对标准偏差（RSD）在1.6% ~5.2%。方法步骤少、时间短,且正确度和精密度高,适用于批量土壤样品中稀土元素的检测。     

Determination of rare earth and other elements in algae by ICP-MS and neutron activation analysis

Several rare earth elements (REEs) and other elements in algae were investigated by ICP-MS and INAA. Algae materials were supplied from an IAEA Intercomparison Study:Chlorella vulg. grown under reduced levels of toxic elements (IAEA-391) and IAEA-393 algae was grown in a medium to which certain toxic elements were added. 34–691 mg of algae samples were dissolved in conc, nitric acid using a microwave sampleppreparation system. REEs could be detected in the order of magnitude of 10⁻³ ng/g by ICP-MS. Activation analysis failed to detect any REEs because of a strong interference due mainly to²⁴Na and³²P. The distriubtion patterns of these REEs in algae slightly differed from those ofCarya sp. and tobacco leaves, and differed significantly from that of fern leaves. The distribution pattern was rather similar to that found in the North American shale composite (NASC).     

Liquid extraction of some rare earth elements with aminomethylphosphine oxides

Methods were developed of the solvent extraction from aqueous solutions of hydrochloric, nitric, and perchloric acids of the triply charged ions of rare earth elements including samarium, lutetium, dysprosium, neodymium, and ytterbium, using as reagents the lipophilic aminomethylphosphine oxides containing two or four dialkylphosphinyl groups, and toluene, chloroform, and methylene chloride as the organic media. The study of the effect of concentration of mineral acids on the degree of metal extraction showed that the highest extraction efficiency of lanthanides is achieved with bis(dihexylphosphinylmethyl)octylamine (I) from perchloric media: extraction degree 80%, whereas extraction from the solutions in two other acids did not exceed 30%. It was shown that the highest selectivity was reached at the extraction of scandium in all the extraction systems. A possible mechanism of extraction is discussed.     

Determination of rare earth and other elements in standard biological samples by ICP-MS and activation analysis

Various rare earth elements (REEs) in standard samples supplied by the IAEA namely mussel (IAEA-142) and lichen (IAEA-336) were examined by ICP-MS and INAA. For ICP-MS, 200 mg each of the samples were dissolved in conc. nitric acid using a microwave sample-preparation system. After repeated concentration-dilution procedures (final volume; 10–20 ml), 1 ml of the sample was supplied for assay. La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb could be detected in the order of magnitude of 10⁻³ ng/g. Activation analysis carried out using 300 mg of the sample powders failed to detect REEs except La, Ce, Sm and Eu because of a strong interference due mainly to²⁴Na and³²P induced in the samples by irradiation. The REE patterns (NASC-normalized) obtained for both the organisms are of the same in their shapes except for all the values for sea animal mussel which are somewhat higher than those for land plant lichen. However, we found a large difference in the other elements contents between the two organisms. For example, Na, Cl, Mg, K, and Ca contents in mussel are about 26, 7, 4.5, 3.5, and 2 times, those in lichen. As the concentrations in the sea water for these elements is from 10² (K and Ca) to 10³ (Na, Cl and Mg) order of magnitude higher than in the land water, the result seems reasonable to assume that the higher the concentration of the element around the organisms the higher its content in the organisms.     

Determination of rare earth elements in geological samples by inductively coupled plasma atomic emission spectrometry with flow injection liquid-liquid extraction.

A direct sampling with organic solvent extracts for simultaneous multi-element determination implemented with inductively coupled plasma atomic emission spectrometry (ICP-AES) associated with a flow injection liquid-liquid extraction (FI-LLE) sample preconcentration method was studied. The "robustness" of the plasma discharge with tributyl phosphate (TBP) loading was diagnosed by using the Mg II 279.55 nm and Mg I 285.21 nm lines intensity ratio. A FI-LLE preconcentration system for rare earth elements (REEs)-nitrate-TBP was established by using a laboratory-designed phase separator. For these elements, an average sensitivity enhancement factor of 64 was obtained with respect to ICP-AES sampling with aqueous solutions. The precision of the method was characterized by a relative standard deviation (%RSD) of 1.8 - 5.2%. A throughput of 27 samples per hour can be achieved with an organic solvent consumption of less than 200 microl per determination. Good results were obtained for the analysis of standard reference materials.     

Determination of trace rare earth elements in natural water by electrothermal vaporization ICP-MS with pivaloyltrifluoroacetone as chemical modifier

A novel method based on gaseous compounds introduction into the plasma as their pivaloyltrifluoroacetone (PTA) chelates was developed for electrothermal vaporization inductively coupled plasma mass spectrometry determination of trace rare earth elements (REEs) in natural water. The factors affecting formation of the chelates and their vaporization behaviors were studied in detail. Under the optimized conditions, the limits of detection (3σ) of REEs for this method were from 0.20 to 0.91 ng L⁻¹, the relative standard deviations for 0.1 μg L⁻¹ REEs were 2.5–9.1% (n = 9), and the linear ranges of calibration curve for REEs covered at least three orders of magnitude. The proposed method had been applied to the determination of trace REEs in water samples of Yangtze river, Han Shui river and East lake (Wuhan), and the recoveries for the spiked water samples were 93–105%.     

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...     

Separation of rare earth elements from uranium by solvent extraction and ion exchange

The detection limit of⁹⁹Tc in (,) radio-activation analysis was determined in the presence of molybdenum and compared with that of⁹⁹Tc in pure materials in the previous paper. The isotopic ratio of molybdenum in a⁹⁹Mo–^99mTc generator column could be simultaneously determined by photon activation analysis.     

Production oriented method for the determination of rare earth and other trace elements in rocks by ICP-MS

The rare earth elements along with Y, Sc, Co, Hf, Nb, Rb, Ta, Th, Ti, U, V and Zr have been determined in ten standard reference materials and ten granitoid samples by inductively coupled plasma mass spectrometry (ICP-MS). Two digestion methods have been used: (a) dissolution with hydrofluoric-perchloric acid followed by fusion of the residue with lithium metaborate, (b) dissolution with hydrofluoric acid-perchloric acid followed by fusion with lithium metaboratesodium perborate and addition of hydrogen peroxide. An evaluation of the two decomposition methods and a comparison of the ICP-MS and X-ray fluorescence results have been carried out. In comparing the two digestion methods, method (b) gave more accurate results for Nb and Ta, and it has been applied to a rock geochemistry project covering whole Finland (about 7000 samples). The statistical stability of the method has been monitored by frequent analyses of reference material SDC-1 (Mica Schist, USGS).     

Production oriented method for the determination of rare earth and other trace elements in rocks by ICP-MS

The rare earth elements along with Y, Sc, Co, Hf, Nb, Rb, Ta, Th, Ti, U, V and Zr have been determined in ten standard reference materials and ten granitoid samples by inductively coupled plasma mass spectrometry (ICP-MS). Two digestion methods have been used: (a) dissolution with hydrofluoric-perchloric acid followed by fusion of the residue with lithium metaborate, (b) dissolution with hydrofluoric acid-perchloric acid followed by fusion with lithium metaboratesodium perborate and addition of hydrogen peroxide. An evaluation of the two decomposition methods and a comparison of the ICP-MS and X-ray fluorescence results have been carried out. In comparing the two digestion methods, method (b) gave more accurate results for Nb and Ta, and it has been applied to a rock geochemistry project covering whole Finland (about 7000 samples). The statistical stability of the method has been monitored by frequent analyses of reference material SDC-1 (Mica Schist, USGS).     

电感耦合等离子体质谱测定富钴结壳中的稀土元素

采用封闭压力酸溶(HF+HNO3)消解样品,以Rh为内标,用电感耦合等离子体质谱测定富钴结壳中的稀土元素。用此方法对3个国家一级标准物质富钴结壳标样(GSMC-1,GSMC-2,GSMC-3)进行了多次测定,结果稀土元素的测定值与标准值相符,多次测定结果的相对标准偏差(RSD,n=5)在0.36%～4.0%之间,加标回收率为90%～106%。基于此方法,对6个富钴结壳样品进行了测定,显示富钴结壳样品中稀土元素的配分曲线与标准物质中稀土元素的配分模式一致。方法适用于富钴结壳样品的批量分析。     

Comparison of single and sequential extraction procedures for the study of rare earth elements remobilisation in different types of soils

With the continual increase in the utilisation of rare earth elements (REE) for industrial and agricultural purposes, research into the environmental and biogeochemical behaviour of REE had attracted much interest in recent times. This study principally describes the distribution of REE in four different types of soils like lateritic soil (S-1), in situ natural soil (S-2), soil contaminated by mining activity (S-3) and accidentally polluted soil (S-4) utilizing the optimised BCR sequential extraction procedure and partial extractions with various types of single extractants such as unbuffered salt solutions 0.1 M NaNO₃, 0.01 M CaCl₂, 1 M NH₄NO₃; complexing agents 0.005 M DTPA and 0.05 M EDTA; acid solutions 0.43 M CH₃COOH and 1 M HCl. Comparison of the sum of the four BCR fractions, which included an aqua regia attack on the residue, with the pseudo-total aqua regia digest values to assess the accuracy of the BCR partioning approach has been undertaken. Partial extraction results with several single extractants have also been reported for all the REE elements including yttrium which have been analysed by the optimised BCR procedure. Results obtained after 24 h extraction with each of the single extractant have also been discussed. The extraction with 1 M HCl during 24 h yielded similar quantities of REE as those released under the combined steps of 1, 2 and 3 of the BCR sequential extraction for all the four different type of soil samples indicating that this reagent can be used successfully to estimate the total extractable contents of REE in various types of soil samples.