Determination of trace elements in uranium oxide by Total Reflection X-ray Fluorescence spectrometry

A study on the applicability of Total Reflection X-ray Fluorescence for the determination of multielements in trace amounts in U₃O₈ matrix has been made. The calibration of the Total Reflection X-ray Fluorescence spectrometer and the validation of the method were done using multielement standards. The trace elements present in U₃O₈ standards and samples were determined after separating the U matrix by solvent extraction using tri-n-butyl phosphate and trioctyl phosphine oxide as extractants. From the aqueous phase the elements K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Rb, Sr, Y, Zr, Pb and Ba, etc., were determined by Total Reflection X-ray Fluorescence using Ga as an internal standard. An intercomparison of the Total Reflection X-ray Fluorescence determined concentrations of the trace elements specific to nuclear fuel, e.g. Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn in U₃O₈ standards/samples with certified concentrations for these elements in U₃O₈ standards and Inductively Coupled Plasma Atomic Emission Spectroscopy determined concentrations in real U₃O₈ samples was also made. The method shows a precision and accuracy better than 5% (1σ) for most elements in concentration range of ng/mL with a sample size of 10 μL.     

Intercomparison of five methods for the determination of trace metals in sea water

Trace elements (Mn, Fe, Co, Zn, Ni, Cu and Cr) were preconcentrated from sea water by retention on Chelex-100 resin, APDC/8-quinolinol complexation followed by extraction with 4-methyl-2-pentanon or Freon-113, or coprecipitation with Mg(OH)₂ or Fe(OH)₂. After consideratin of analytical blanks, extraction efficiency, precision preconcentration factor, and suitability for operation on board ship, the best results were obtained by preconcentrating Mn, Fe, Co, Zn, Ni and Cu on Chelex-100 resin and coprecipitation of chromium(III) and (VI) with Fe(OH)₂. Graphite-furnace atomic absorption spectrometry and inductively-coupled plasma atomic emission spectrometry were used for the final measurements. The accuracy of the method was tested by using the reference sea water sample NASS-1.     

A solid phase extraction using a chelate resin immobilizing carboxymethylated pentaethylenehexamine for separation and preconcentration of trace elements in water samples

A chelate resin immobilizing carboxymethylated pentaethylenehexamine (CM-PEHA resin) was prepared, and the potential for the separation and preconcentration of trace elements in water samples was evaluated through the adsorption/elution test for 62 elements. The CM-PEHA resin could quantitatively recover various elements, including Ag, Cd, Co, Cu, Fe, Ni, Pb, Ti, U, and Zn, and rare earth elements over a wide pH range, and also Mn at pH above 5 and V and Mo at pH below 7. This resin could also effectively remove major elements, such as alkali and alkaline earth elements, under acidic and neutral conditions. Solid phase extraction using the CM-PEHA resin was applicable to the determination of 10 trace elements, Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, V, and Zn, in certified reference materials (EnviroMAT EU-L-1 wastewater and ES-L-1 ground water) and treated wastewater and all elements except for Mn in surface seawater using inductively coupled plasma atomic emission spectrometry. The detection limits, defined as 3 times the standard deviation for the procedural blank using 500 mL of purified water (50-fold preconcentration, n = 8), ranged from 0.003 μg L⁻¹ (Mn) to 0.28 μg L⁻¹ (Zn) as the concentration in 500 mL of solution.     

高纯钛的辉光放电质谱法多元素分析

采用辉光放电质谱法(GD-MS)测定高纯钛中Mg、Al、Cr、Fe、V、Mn、Co、Ni、Cu、Zn、As、Sn、Sb、Ta、W、Pb、Bi等痕量杂质元素,并对GD-MS工作参数及条件进行了优化。主要元素与内标校正ICP-MS法定量分析的结果一致,对结果差异的原因进行分析,论述了Element GD辉光放电质谱仪在痕量杂质元素分析方面的优势。     

Microwave assisted digestion of atmospheric aerosol samples followed by inductively coupled plasma mass spectrometry determination of trace elements

A microwave digestion method in a closed vessel was developed for the determination of trace metals in atmospheric aerosols using inductively coupled plasma mass spectrometry (ICP-MS). A recovery study for the elements V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sb, and Pb was conducted using multi-elemental standard solutions, NIST 1633b Trace Elements in Coal Fly Ash, and NIST 1648 Urban Particulate Matter. A simple digestion method using only HNO₃/H₂O₂ gave good recoveries (90%–108%) for all elements except Cr in SRM 1648, but yielded low recoveries for SRM 1633b. A more robust method using HNO₃/H₂O₂/HF/H₃BO₃ yielded higher recoveries (82%–¶103%) for the lighter elements (V – Zn) in SRM 1633b, and improved the Cr recovery in SRM 1648, but decreased the Se recovery in both SRMs. A comparative analysis of aerosol samples obtained at a remote mountain location Nathiagali, Pakistan (2.5 km above mean sea level), and Mayville, New York, downwind from the highly industrialized Midwestern United States, was carried out using Instrumental Neutron Activation Analysis (INAA) for the elements Cr, Mn, Fe, Co, Zn, As, Se, and Sb. The simple digestion method yielded excellent agreement for Cr, Fe, Zn, As, Se, and Sb, with slopes of the ICP-MS vs. INAA regressions of 0.90–1.00 and R² values of 0.96–1.00. The regressions for Mn and Co had slopes of 0.82 and 0.84 with R² values of 0.83 and 0.82, respectively. Addition of HF/H₃BO₃ did not improve the correlation for any of the elements and degraded the precision somewhat. The technique provides sensitivity and accuracy for trace elements in relatively small aerosol samples used in atmospheric chemistry studies related to SO₂ oxidation in cloud droplets. The ability to determine concentrations of a very large number of elements from a single analysis will permit source apportionment of various trace pollutants and hence strategies to control the sources of air pollution. This is particularly important as the health effects of particulate matter are increasingly recognized.     

Pure graphite as a reference material for the determination of trace elements — an interlaboratory collaborative study

Seven synthetic graphite powders of different grade of purity were analyzed by means of INAA, WDXRF, EDXRF, DC-OES directly and using ICP-MS, ICP-OES, ETAAS and FAAS in combination with various sample preparation techniques. On the basis of a statistical evaluation of the results obtained, for the trace elements Al, Ca, Cr, Cu, Fe, Mn and Ni, reference values were established and, for the elements As, Co, Mg, Mo, Pb, Sb, Si, Sr, Ti, V, Zn and Zr, informative values are given. The analyzed reference materials are commercially available.     

Determination of trace impurities in semi-conductor grade PCl3 and POCl3-A d.c. arc spectrochemical method

Summary A spectrochemical method for the determination of traces of Al, Co, Cu, Cr, Fe, Mn, Mg, Ni, Pb, Sb, Sn, Ti and V in semiconductor grade PCl₃ and POCl₃ has been developed. 25ml of the sample is evaporated in a stream of nitrogen and the residual phosphoric acid containing the impurities is treated with bismuth nitrate to co-precipitate the impurities on BiPO₄. The phosphate is spectrographically analysed employing the d.c. arc with Ga as the internal standard and LiF as the carrier. The range of concentration determined is 5–200 ppm and the precision of the method in terms of coefficient of variation is 9–20% for the different impurities.

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Bestimmung von Spurenverunreinigungen in Halbleiter-Phosphortrichlorid und -Phosphoroxidchlorid — Ein spektralanalytisches Verfahren mit Gleichstrombogen

Zusammenfassung Ein Verfahren wurde ausgearbeitet zur Bestimmung von Spuren Al, Co, Cu, Cr, Fe, Mn, Mg, Ni, Pb, Sb, Sn, Ti und V in Halbleiter-PCl₃ und-POCl₃. 25 ml der Probe werden im Stickstoffstrom eingedampft und die zurückbleibende Phosphorsäure, die die Verunreinigungen enthält, wird mit Bismutnitrat behandelt, wobei die Verunreinigungen an BiPO₄ mitgefällt werden. Das Phosphat wird spektralanalytisch untersucht (Gleichstrombogen, Ga als als innerer Standard, LiF als Träger). Die Elemente wurden im Bereich von 5–200 ppm analysiert. Der Variationskoeffizient lag zwiwchen 9 und 20%.

     

Simultaneous on-line preconcentration and determination of trace metals in environmental samples by flow injection combined with inductively coupled plasma mass spectrometry using a nanometer-sized alumina packed micro-column

A flow injection (FI) on-line preconcentration procedure by using a nanometer-sized alumina packed micro-column coupled to inductively coupled plasma mass spectrometry (ICP-MS) was described for simultaneous determination of trace metals (V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb) in the environmental samples. The effects of pH value, sample flow rate, preconcentration time, and interfering ions on the preconcentration of analytes have been investigated. Under the optimized operating conditions, the adsorption capacity of the nanometer-sized alumina for V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb were found to be 11.7, 13.6, 15.7, 9.5, 12.2, 13.3, 17.1, 17.7 and 17.5 mg g⁻¹, respectively. With 60 s preconcentration time and 60 s elution time, an enrichment factor of 5 and the sampling frequency of 15 h⁻¹ were obtained. The proposed method has been applied to the determination of trace metals in environmental certified reference materials and natural water samples with satisfactory results.     

Direct analysis of Al<Subscript>2</Subscript>O<Subscript>3</Subscript> powders by total reflection X-ray fluorescence spectrometry

A direct analysis procedure for the determination of trace impurities of Ca, V, Cr, Mn, Fe, Ni, Cu, Zn and Ga in Al₂O₃ ceramic powders by total reflection X-ray fluorescence spectrometry (TXRF) is described. The powders were analysed in the form of slurries containing 1–10 mg mL^–1 of powder. The use of the procedure in the case of powders with differing grain size and for different slurry concentrations was investigated. Three different quantification possibilities were compared, namely the use of Al as a matrix component, the use of Fe as a trace element contained in the sample or of Co added in concentrations of 200 g g^–1 as internal standard. The homogeneity of elemental distributions in sample layers deposited on the TXRF quartz carriers by evaporating 5 L of the 10 mg mL^–1 slurries was studied by scanning the 4- to 5-mm-diameter spots of two samples by synchrotron radiation TXRF at Hasylab. For powders with differing graininess but mainly finer than about a few 10 m, no systematic influence of the grain size on the accuracy of the determinations of Ca, V, Fe, Ni, Cu and Zn could be observed. The measurement precision, however, seemed to be limited by inhomogeneous distributions of the trace elements in the samples as testified by the synchrotron radiation TXRF scans. Detection limits of the developed TXRF procedure for Ca, V, Cr, Mn, Fe, Ni, Cu, Zn and Ga were found to be in the 0.3–7 g g^–1 range and were shown to increase slightly with the grain size of the samples. Quantification using Al (matrix) as internal standard led to systematically higher values out of the accuracy required, whereas the other two approaches in all cases led to reliable results.Dedicated to the memory of Wilhelm Fresenius     

Determination of trace levels of metal ions in water samples by inductively coupled plasma mass spectrometry after on-line preconcentration on SO3-oxine CM-cellulose

Summary A method utilizing a miniature chelated ion-exchanger column of SO₃-oxine CM-cellulose has been developed to increase the sensitivity for multielement measurements by inductively coupled plasma mass spectrometry (ICP-MS). This matrix/analyte separation and preconcentration technique has been used to preconcentrate Mn, Co, Ni, Cu, Cd, and Pb from natural water samples. The multielement detection limits are in the low ppt (pg/mL) range. This FIA-ICP-MS method has been applied to the determination of various trace levels of metal ions in riverine reference material SLRS-2 and open ocean seawater reference material NASS-3.     

Pure graphite as a reference material for the determination of trace elements — an interlaboratory collaborative study

 Seven synthetic graphite powders of different grade of purity were analyzed by means of INAA, WDXRF, EDXRF, DC-OES directly and using ICP-MS, ICP-OES, ETAAS and FAAS in combination with various sample preparation techniques. On the basis of a statistical evaluation of the results obtained, for the trace elements Al, Ca, Cr, Cu, Fe, Mn and Ni, reference values were established and, for the elements As, Co, Mg, Mo, Pb, Sb, Si, Sr, Ti, V, Zn and Zr, informative values are given. The analyzed reference materials are commercially available. Received: 12 February 1996/Revised:27 March 1996/Accepted:2 April 1996     

Microwave digestion-ICP-MS for elemental analysis in ambient airborne fine particulate matter: rare earth elements and validation using a filter borne fine particle certified reference material

NIST standard reference material SRM 2783 was employed to validate a high temperature, high pressure, two-stage microwave assisted acid digestion procedure using HNO₃, HF and H₃BO₃ developed for the analysis of trace elements (including rare earths) in atmospheric fine particulate matter (PM_2.5) prior to inductively coupled plasma mass spectrometry (ICP-MS). This method quantitatively solubilized Na, Mg, Al, K, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sb, Cd, Cs, Ba, Pb, Th, U and several rare earth elements (REEs) (La, Ce, Pr, Nd, Gd, Dy, Er, Sm and Eu) from SRM 1648 and SRM 2783. A small amount of HF in the first stage was required to dissolve silicates necessitating the corresponding addition of H₃BO₃ in second stage to dissolve fluoride precipitates of Mg, La, Ce and Th. The optimized microwave dissolution—ICP-MS method detected Na, Mg, Al, K, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Cd, Mo, Sb, Cs, Ba, La, Ce, Pr, Nd, Sm, Gd, Pb, Th and U at trace to ultra-trace levels in ambient airborne fine particles from three sites in North Carolina. La to light lanthanide signature ratios suggested that soil and motor vehicles are the dominant REE sources in SRM 2783 and PM_2.5 samples collected during this study.     

Simultaneous multi-element analysis for trace metals in sea water by inductively-coupled plasma/atomic emission spectrometry after batch preconcentration on a chelating resin

Batch treatment with Chelex-100 resin was investigated for preconcentration of trace metals in sea water followed by determination by inductively-coupled plasma atomic emission spectrometry. The preconcentration conditions such as resin weight, stirring time, and amount of ammonium acetate buffer solution were carefully examined for effective multi-element preconcentration from sea water. The resin weight could be decreased to 0.5 g (dry weight) for 1 l of sea water, which was much less than that required in the column method, and a preconcentration factor of 100 was achieved. Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Y, Mo, Cd and Pb in sea water were measured with good precision. The detection limits ranged from 6 to 180 ng l^?1. The time required for one sample by the batch method was only 3 h.     

Determination of trace elements in ambient aerosol samples

A microwave-assisted digestion procedure using HNO₃, HF, and H₂O₂ has been developed for analysis of elements in ambient particulate matter (PM). The samples are collected on cellulose filters and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The ICP-MS is calibrated with external standards, and recovery of analytes is tested with NIST SRM 1648 Urban Dust. This method has been used to quantify the airborne concentrations of a large number of elements, including Ag, As, Ba, Be, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, K, Li, Mg, Mn, Mo, Ni, Pb, Rb, Se, Sb, Sr, Ti, Tl, V, and Zn. For the majority of these elements, recovery of the NIST SRM is within 15% of the certified values.     

An off-line automated preconcentration system with ethylenediaminetriacetate chelating resin for the determination of trace metals in seawater by high-resolution inductively coupled plasma mass spectrometry

A novel automated off-line preconcentration system for trace metals (Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in seawater was developed by improving a commercially available solid-phase extraction system SPE-100 (Hiranuma Sangyo). The utilized chelating resin was NOBIAS Chelate-PA1 (Hitachi High-Technologies) with ethylenediaminetriacetic acid and iminodiacetic acid functional groups. Parts of the 8-way valve made of alumina and zirconia in the original SPE-100 system were replaced with parts made of polychlorotrifluoroethylene in order to reduce contamination of trace metals. The eluent pass was altered for the back flush elution of trace metals. We optimized the cleaning procedures for the chelating resin column and flow lines of the preconcentration system, and developed a preconcentration procedure, which required less labor and led to a superior performance compared to manual preconcentration (Sohrin et al. [5]). The nine trace metals were simultaneously and quantitatively preconcentrated from ∼120 g of seawater, eluted with ∼15 g of 1 M HNO₃, and determined by HR-ICP-MS using the calibration curve method. The single-step preconcentration removed more than 99.998% of Na, K, Mg, Ca, and Sr from seawater. The procedural blanks and detection limits were lower than the lowest concentrations in seawater for Mn, Ni, Cu, and Pb, while they were as low as the lowest concentrations in seawater for Al, Fe, Co, Zn, and Cd. The accuracy and precision of this method were confirmed by the analysis of reference seawater samples (CASS-5, NASS-5, GEOTRACES GS, and GD) and seawater samples for vertical distribution in the western North Pacific Ocean.     

煤中痕量元素在循环流化床锅炉中的迁移行为与富集特性

对天津市某电厂循环流化床(CFB)锅炉燃用的原煤及燃烧产物底灰、飞灰、细飞灰(≤50 μm)进行痕量元素含量的测定,分析了Be、Zn、Hg、V、Cr、Mn、Co、Ni、Cu、As、Se、Cd、Pb 13种痕量元素在燃烧过程中的迁移行为,揭示了痕量元素在CFB锅炉中的分配、富集特性。结果表明,CFB锅炉中,较低的炉温对于痕量元素的迁移富集产生了较大的影响。由相对富集系数得知,Be、V、Co、Se在底灰中耗散,在飞灰中富集,Zn、Mn倾向于在底灰中富集,元素Cd、Pb、Ni、Cu挥发性较强,在底灰和飞灰中均是耗散。As受钙氧化物影响,挥发性表现并不明显。Hg在底灰和飞灰中相对富集系数均很低,表明Hg在整个燃烧过程中以气态形式排放;Hg、As、Se、V、Cr、Mn、Co、Ni、Cu、Zn、Pb均有向小颗粒物中富集的趋势。根据相对富集系数以及研究的13种元素在低温CFB锅炉中的迁移行为,将这些元素分为三类:A类(E_R<0.1),主要是以气态形式排放元素Hg;B类(0.1R≤0.85),较易挥发元素As、Be、Ni、Cu、Se、Cd、Pb、Co、V;C类(E_R>0.85),主要残留在固体产物中元素Zn、Mn、Cr。     

Comparitive study of the sample decomposition procedures in the determination of trace and rare earth elements in anorthosites and related rocks by ICP-MS

ICP-MS has been used for the determination of over 30 geochemically significant trace elements (Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Cs, Ba, Hf, Ta, Pb, Th, U and REEs) in anorthosites and related rock reference samples. Open acid digestion, pressure decomposition using HF, HNO₃ and HClO₄, and a fusion method using lithium metaborate and subsequent dissolution in dil. HNO₃ were adopted for the decomposition of these rock samples before analysis. The dissolution problems and interference effects are discussed. Rh and Bi were used as internal standards. The first set of data on several rare earths and other trace elements in the Russian anorthosite reference sample, MO-6 are presented along with data on other samples. The data are compared with the available data. The results obtained with different dissolution methods were found to be in good agreement for the majority of the trace elements. The accuracy and precision achieved (better than 6% RSD in most cases) suggested that the data obtained by ICP-MS for such samples are best suited for geochemical interpretations.     

Preconcentration by dithiocarbamate extraction for determination of trace elements in natural waters by inductively-coupled plasma atomic emission spectrometry

Preconcentration by dithiocarbamate extraction into 2-ethylhexyl acetate for simultaneous determination of trace elements in natural water is described. After 250-fold concentration, the organic phase is used directly for inductively-coupled plasma atomic emission spectrometry. Thirteen elements (As, Se, Mo, Zn, Cd, Ni, Co, Sn, Fe, Cr(VI), Pb, V and Cu) are simultaneously concentrated at pH 4.3 with the combination of ammonium tetramethylenedithiocarbamate and dibenzylammonium dibenzyldithiocarbamate and are determined in the extract; Mn and Cr(III) are also determined after preconcentration at pH 6.9 with the same chelating agents. Lake waters are analyzed by this method.     

Determination of impurities in high-purity niobium(V) oxide by high-resolution continuum source graphite furnace atomic absorption spectrometry after sorption preconcentration

Method of sorption–atomic-absorption determination of Co, Cr, Cu, Fe, Mn, and Ni in samples of high-purity Nb₂O₅ with heterochain S,N-containing sorbents was developed. The method is based on the sorption preconcentration of trace impurities followed by their determination by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS). Selectivity of three original inhouse synthesized S,N-containing heterochain sorbents was studied. The recoveries of Co, Cr, Cu, Fe, Mn, and Ni using heterochain sorbents OKS, MTH, and GLSH were 100, 80, and 76%, correspondingly. Sorbent “OKS”, which provided the quantitative recovery of trace impurities, was chosen for further research. The sorption conditions for chloride solutions of different acidities (0.1–3 M HCl) were studied and optimized. Using the conditions established for the sorption and HR CS GFAAS analysis, trace Co, Cr, Cu, Fe, Mn, and Ni were determined in high purity Nb₂O₅ with a relative error less than 5%. The trueness control of the obtained results is confirmed by the “added–found” method. The developed method allows us to determine concentrations of analytes: 0.02–0.20 ppm Co, 2.0–3.3 ppm Cr, 0.2–1.5 ppm Cu, 6.0–21.0 ppm Fe, 0.6–0.8 ppm Mn, and 2.8–3.5 ppm Ni. The proposed methodology can be successfully extended to the determination of various trace elements in other high-purity inorganic materials.     

Determination of trace elements by inductively coupled plasma mass spectrometry of biomass and fuel oil reference materials using milligram sample sizes

Most of the analytical techniques used to quantify elements associated with solid samples suffer from high detection limits and cannot be used for trace elements in biomass samples, particularly when only 20 mg are available for analysis. Inductively coupled plasma mass spectrometry (ICP-MS) can achieve detection limits of parts-per-trillion with liquid sample introduction by solution nebulisation. This technique was therefore tested with two standard biomass reference materials: oriental tobacco leaves and cabbage leaves. Two preparations successfully used on coal standards were used to digest the solid samples: a total digestion method (wet ashing digestion) and a partial leaching (microwave extraction). The concentrations of up to seventeen elements (As, Ba, Be, Cd, Co, Cr, Cu, Ga, Mn, Mo, Ni, Pb, Sb, Se, Sn, V and Zn) were measured after the two preparations. The accuracy and sensitivity of the measurements improved when the dilution factor decreased from 5000 to 1000 and to 500. Since the proportion of mineral matter in biomass samples is small (5%), the microwave digestion extracted elements that are generally not completely extracted from coal samples (e.g. Sb). However, some trace element concentrations were below the limit of quantification after microwave extraction, even with a reduced dilution factor (As, Se and Mo) and could not be quantified. A fuel oil was also digested. The trace element concentrations were very low (between 28 and 0.1 microgram g(-1)) but acceptable results were obtained by applying a dilution factor of 100. Only six elements in the fuel oil (As, Ba, Co, Ni, Se and V) had certified or indicated values. Factors affecting the accuracy and sensitivity of the analyses are discussed. The reproducibility of analysis of the tobacco leaf standard was checked over a period of nine months by both digestion methods. The wet ashing method gave acceptable reproducibility for Ba, Cd, Co, Cu, Ga, Mn, Mo, Ni, Pb, V and Zn but poor precision for Cr, Se and Sn and showed evidence of residual chloride interference for As. The microwave extraction gave good reproducibility for As, Ba, Cd, Co, Cr, Cu, Mo, Ni and Zn but poor precision for Se and low recoveries for Ga, Mn, Sn and V. In spite of the small quantities of material analysed, it proved possible to determine the trace elements at levels down to 0.1 microgram g(-1) in the reference materials.