bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of Synthetic Calibration Materials for Use in the Microanalysis of Oxide Minerals by Direct Fusion in High‐Purity Graphite Electrodes: Preliminary Results for Quartz and Rutile
Authors: Ødegård Magne
Published: May 2007

This paper describes a technique for the preparation of synthetic calibration materials for use in laser ablation inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) and other microtechniques for mineral analysis. The method is based on direct fusion in high‐purity graphite electrodes, and the requisite temperatures for melting are obtained by resistance heating using a welding rectifier as the power source. The technique has been tested on quartz (SiO2) and rutile (TiO2) for a relatively large range of elements, including all the rare earth elements. Different starting materials for preparation of calibration materials were studied, and it is shown that many natural materials form separate phases during fusion, resulting in unusable calibration materials for microanalysis. However, calibration materials prepared fully synthetically from oxides and/or element nitrates in solution were found to be of good homogeneity, and this preparation technique was used throughout in this work. The quality of the calibration materials for quartz and rutile was assessed by LA‐ICP‐MS, using Si and Ti as internal standard elements respectively. The NIST SRM 612 and 614 glass standards were used to assess the accuracy of the calibration materials for quartz. Calibration curves based on two independently prepared sets of calibration materials and the two NIST glasses are shown for a number of elements, demonstrating excellent agreement between the NIST glasses and the synthetically prepared quartz glasses. Vesicles are shown to form in the SiO2 glasses, but this does not influence their value as calibration materials, provided that a reference element is used as an internal standard. The advantages of fusion in high‐purity graphite electrodes are emphasised, particularly the very high sublimation point of graphite, its very high state of purity, the very short melting and quench time, the speed and simplicity of the method, and the low risk of introducing impurities. Extension of the method to other minerals and applications is discussed.
Precise Quantitative Determination of Niobium at Low Level Concentrations in Geological Samples by WD‐XRF
Authors: Etoubleau Joël , Cambon Pierre , Bougault Henri , Joron Jean‐Louis
Published: May 2007

We show in this paper that wavelength dispersive X‐ray fluorescence spectrometry (WD‐XRF) can provide high quality determinations (in terms of accuracy and precision) of Nb in rocks at low level concentrations comparable with data from much more sensitive analytical techniques. Two different sample preparation methods were investigated and combined with a long count time XRF strategy. We first developed a standard additions procedure for rock powders in conjunction with a careful evaluation of the position of analytical lines (peak and background). The precision (2s) varied from within 0.03 μg g−1 to 0.2 μg g−1 in the 0‐5 μg g−1 concentration range, and the detection limit was 0.2 μg g−1. We then separated Nb from the geological matrix using the chemical procedure described by Rehkämper (1994); after separation, Nb was collected on an anion‐exchange membrane which was directly excited by X‐rays. This method yielded a precision (2s) of 0.2 μg g−1 at the μg g−1 level if 100 mg of sample was used, the detection limit being dependent on the mass of sample studied. Detailed descriptions of analytical procedures are given, particularly of innovative aspects of Nb collection on membranes. XRF results obtained by the two sample preparation methods were compared with instrumental neutron activation (INAA) Ta analysis. We found that the ion‐exchange method tended to provide Nb concentrations which were about 10‐15% lower than concentrations found by the standard additions method. We report data for fifteen international reference materials (NIM‐N, AL‐I, AN‐G, BE‐N, MRG‐1, JA‐1, JB‐2, JB‐3, JA‐2, JF‐1, JGB‐1, BIR‐1, DNC‐1, W‐1, W‐2), for which our XRF results are in good agreement with literature data.
Determination of Trace Elements in Twenty Six Chinese Geochemistry Reference Materials by Inductively Coupled Plasma‐Mass Spectrometry
Authors: Liang Qi , Grégoire D. Conrad
Published: May 2007

We report new data for thirty seven elements determined in twenty six Chinese geochemistry reference materials using inductively coupled plasma‐mass spectrometry and a reliable and simple dissolution technique. One hundred milligrams of sample were digested with 1 ml of HF and 0.5 ml of HNO3 in PTFE‐lined stainless steel bombs heated to 200 °C for 12 hours. Insoluble residues were dissolved using 6 ml of 40% v/v HNO3 heated to 140 C for 3 hours. Analytical calibration was accomplished using aqueous standard solutions. Rhodium was used as an internal standard to correct for matrix effects and instrument drift. Precisions were typically better than 5% RSD. Most of the data presented here agree well with the published certified values. For the elements Zr, Hf and most other trace elements, the measured values were less than 10% in error when compared to certified values.
GeoPT5. An International Proficiency Test for Analytical Geochemistry Laboratories ‐ Report on Round 5
Authors: Thompson Michael , Potts Philip J. , Kane Jean S. , Wilson Stephen
Published: May 2007

Results are presented from the seventy two laboratories participating in GeoPT5, round five of the international proficiency testing programme for analytical geochemistry laboratories. The sample for round five, AMH‐1 (Mount Hood andesite), was distributed during March 1999 and participating laboratories were asked to analyse the sample using their routine techniques and submit results to the steering by 15th June 1999. In this report, contributed data are listed together with the derived z‐scores from which participating laboratories can assess their analytical performance. Z‐scores in the range ‐2 to 2 are considered satisfactory. Z‐score values that lie outside this range may indicate unsuspected analytical bias. The distinctive feature of the present round is that AMH‐1 is a candidate reference material prepared by the USGS and it is intended that the present proficiency testing data will contribute to the reference material characterisation programme.
Observations on New Approaches for the Determination of Platinum‐Group Elements, Gold and Silver in Different Geochemical Samples from Siberia and the Far East
Authors: Tsimbalist Valentina G. , Anoshin Gennady N. , Mitkin Valentin N. , Razvorotneva Ljudmila I. , Golovanova Nadezhda P.
Published: May 2007

Some recent experiments on the determination of Au and the platinum‐group elements (PGE) in geochemical samples are reviewed. Emphasis is given to the determination of ultra‐low levels of PGE concentrations in resistant matrices, including chromites, molybdenites and ultrabasic ores. The problems and features of PGE determination in samples of various chemical composition are considered. For each sample type studied, a series of sample preparation techniques are proposed. These techniques included acid digestion, fusion with sodium peroxide, cold sintering with an oxidizing mixture of Na2O2+ Na2CO3 and also oxidizing fluorination with bromine trifluoride. A new approach for preparing geochemical material prior to digestion, based on mechano‐chemical activation with simultaneous hyperfine grinding, is proposed and studied. The instrumental determination of PGE contents was carried out directly by AAS from extracted organic phases. It was found that a combination of digestion processes was required to achieve geochemical background levels of Au and PGE concentrations with the following detection limits: Pd, Rh ‐ 1 ng g−1, Pt, Ru ‐ 10 ng g−1, Au ‐ 0.2 ng g−1, Ag ‐ 0.1 ng g−1. The uncertainty in PGE and Au determination in geochemical samples is dependent on metal concentration, and also on their distribution in samples. The total analytical uncertainty of the proposed method is between 15‐30%.
Comparison of Synchrotron Radiation X‐Ray Fluorescence with Conventional Techniques for the Analysis of Sedimentary Samples
Authors: Phedorin Michael A. , Bobrov Vladislav A. , Chebykin Evgeny P. , Goldberg Evgeny L. , Melgunov Michael S. , Filippova Svetlana V. , Zolotarev Konstantin V.
Published: May 2007

A comparison is made of elemental analyses of sediment samples (lake bottom sediments and sediments from the petroliferous Bazhenovka Formation) by five competitive methods (synchrotron radiation X‐ray fluorescence (SR‐XRF), INAA, ICP‐MS, AAS and traditional XRF). The object of this study was to identify the most suitable analytical techniques for applications in sedimentary geochemistry. Advantages and shortcomings of the five techniques were considered with respect to applications related to studies of palaeo‐climate changes recorded in sedimentary cores from Lake Baikal and the geochemical stratigraphy of the Bazhenovka Formation, which is rich in organic material. We have concluded that SR‐XRF was the best technique for producing extensive analytical data series, from the point of view of its speed, ease of application, cost, non‐destructive nature and sensitivity, which allowed for the simultaneous determination of more than twenty elements of geochemical interest in small samples of sediments. An additional benefit of the method was demonstrated when used for the independent certification of geological reference materials. International reference samples BIL‐1 and SDO‐1 were certified by means of this method without use of reference materials. Analyses were based on the physics of the theory of energy transport.
Some Observations on the Determination of Gold and the Platinum‐Group Elements in Black Shales
Authors: Mitkin Valentin N. , Galizky Alexander A. , Korda Tamara M.
Published: May 2007

This research compares various ways of applying oxidative chemical decomposition to the analysis of gold‐bearing black shale ores from the Russian Natalka and Sukhoj Log deposits. This study was conducted as part of the certification program for the Russian candidate black shale reference materials SLG‐1 and SCHS‐1 and also because of the paucity of data available on the determination of the platinum group elements (PGE) in analogous sample types. We report direct evidence of PGE volatilisation from black shale materials when processed in the presence of oxygen. We also developed a comprehensive analytical scheme for the quantitative determination of PGE in all phases (gaseous and ash) produced during slow combustion of carbonaceous materials in oxygen.

This study has shown that during combustion in oxygen at 600 °C, PGE contained in the Natalka black shale ores are lost as gaseous reaction products. Thus, the volatilized PGE (recovered in traps) account for up to 14% Pt, 40% Pd, 40% Ru and 10 % Ir relative to their total concentrations in a carbonaceous concentrate. It was also established that in the process of combustion, Au quantitatively remains in the ash cake.

In order to avoid the deleterious effects of oxygen on the volatility of the PGE, we propose a new comprehensive sample decomposition method based on the application of fluoroxidants such as BrF3and KBrF4. This method was validated using samples of black shale ores and their processing products by comparing our results with those obtained independently using sealed autoclave processing of the same materials. It was shown that PGE in black shale ores and their processing products not only exist in commercially exploitable quantities but that a small proportion of PGE compounds are soluble in alcohol. We propose that in gold‐bearing black shale ores, PGE are present as organometallic compounds.
Uranium Concentration in Altered Brown Coals Located under Burnt Rocks from the Kansk‐Achinsk Basin, West Siberia
Authors: Gavshin Vsevolod M. , Miroshnichenko Leonid V.
Published: May 2007

West Siberian brown coals from the Kansk‐Achinsk basin and their combustion products are generally characterized by a low uranium content. In some places where brown coal has been altered (losing density, becoming cracked or friable), the uranium content has increased by concentrations ranging from 1001000 μg g−1. At these locations distinct signs of underground fires are visible. The uranium distribution patterns suggest that the burnt organic matter was a source of uranium and altered varieties of coal serve as a geochemical barrier to uranium transport.
Molybdenum Concentrations Measured in Eleven USGS Geochemical Reference Materials by Isotope Dilution Thermal Ionisation Mass Spectrometry
Authors: Wieser Michael E. , DeLaeter John R.
Published: May 2007

Molybdenum concentrations in eleven USGS geochemical reference materials AGV‐1, BCR‐1, BHVO‐1, BIR‐1, DNC‐1, DTS‐1, G‐2, GSP‐1, MAG‐1, PCC‐1 and W‐2 were measured by isotope dilution thermal ionisation mass spectrometry (ID‐TIMS). In every case but one, the concentrations determined in this study were significantly lower than the current consensus values. Molybdenum concentrations determined by ID‐TIMS are inherently more accurate and precisions may be up to an order of magnitude higher than those measured by other analytical techniques.
Coupling Size‐Exclusion Chromatography and ICP‐MS to Investigate the Speciation of Platinum‐Group Elements in Environmental Samples
Authors: Menzel Christoph M. , Berner Zsolt , Stüben Doris
Published: May 2007

The applicability of size‐exclusion chromatography (SEC) coupled online with a high resolution ICP‐MS (HR‐ICP‐MS) to investigate the speciation of the platinum‐group elements (PGE), Rh, Pd and Pt, was evaluated. Experiments were carried out to determine the efficiency of different hydrophilic and hydrophobic size‐exclusion gel materials to select the optimal eluent in respect of resolution, recovery, reproducibility and limit of detection. The suitability of HR‐ICP‐MS as a reliable detection instrument at low pg ml−1 levels was investigated by examining possible mass interferences with Rh, Pd and Pt. Laboratory experiments demonstrated the interaction and capability of forming complexes of humic substances with PGE, demonstrating the potential role of these ubiquitous natural substances in the mobilisation of PGE in the environment.
The Precision and Sensitivity of Thermal Ionisation Mass Spectrometry (TIMS): An Overview of the Present Status
Authors: Birck Jean Louis
Published: May 2007

This paper illustrates that sample size cannot be reduced below a theoretical limit and still achieve the highest precision obtainable on modern mass spectrometers. Reproducibility at the few ppm level is achievable and is related essentially to ion counting statistics. The number of atoms necessary to carry out such measurements is related directly to the sensitivity of the instrumentation. As most of the elements of interest are not major constituents of natural silicates, a lower limit to the size of the starting sample is assessed. Even for a number of elements for which very high ion per atom yields are attained by TIMS, minimum sample mass is an important limiting factor for precious or rare samples and may reduce the scientific output of experiments or place a major constraint on the sampling strategy itself. For rare meteorites or individual Martian samples expected to be returned in amounts at the gramme scale for rocks or at the microgramme scale for dust, the high sensitivity of TIMS is a requirement. Nevertheless, a compromise has to be found between sample consumption and the minimal desirable precision for a useful isotopic measurement.
Precise Determination of Rubidium in Geological Reference Materials by ID‐TIMS and WD‐XRF: A Discussion for the Basalt BIR‐1
Authors: Bollinger Claire , Etoubleau Joël
Published: May 2007

Data were obtained for rubidium in six geological reference materials by isotopic dilution thermal ionisation mass spectrometry (ID‐TIMS) and wavelength dispersive X‐ray fluorescence spectrometry (WD‐XRF). The results found by one technique compare very well with the other within the respective analytical uncertainties and are also in good agreement with data from previously published values. The particular case of low Rb determinations in reference sample BIR‐1 is discussed.
Combination of ICP‐AES and Instrumental Neutron Activation Analysis as Effective Methods for Studying Distribution of Elements in Soil and Plants
Authors: Shtangeeva Irina , Vuorinen Antti , Rietz Bernd , Carlson Liisa
Published: May 2007

A detailed characterisation was carried out for soil sampled from sites with different levels of contamination before and after the cultivation of oats and barley. Mineralogical composition, concentration of exchangeable cations, dynamics of soil pH and acid neutralisation buffer capacity of the soil were studied. A total of 21 elements in the soil and 28 elements in the plants were determined by instrumental neutron activation analysis. Distribution of Al, Cr, Mn, Fe, Co, Ni, Cu, Zn and Pb in soil leachates was studied by sequential leaching procedure and ICP‐AES. It was found that plants significantly affect most of the soil characteristics including the leaching of heavy metals.
Direct Determination of Lead Isotope Ratios by Laser Ablation‐Inductively Coupled Plasma‐Quadrupole Mass Spectrometry in Lake Sediment Samples
Authors: Aries Sébastien , Motelica‐Heino Mikael , Freydier Rémi , Grezes Thierry , Polvé Mireille
Published: May 2007

A direct method for the determination of lead isotopic ratios by laser ablation‐inductively coupled plasma‐quadrupole mass spectrometry (LA‐ICP‐QMS) is presented. Samples of lake sediments were ground and pressed as pellets before being analysed. Mass bias was corrected by analysing an external calibration sample manufactured with pure silica doped with NIST SRM 981 solution. The efficiency of the mass bias correction was checked by comparing the ICP‐MS data with lead isotopic ratios determined by thermal ionisation mass spectrometry (TIMS). The average long term reproducibilities were 0.40%, 0.40%, 0.20% and 0.30% (RSD) respectively for the 206Pb/204Pb, 207Pb/204Pb, 206Pb/207Pb and 208Pb/206Pb ratios. The method was applied to the study of lake sediment samples, in order to determine the amount and origin of historical contamination by lead.
Boron and Oxygen Isotope Composition of Certified Reference Materials NIST SRM 610/612 and Reference Materials JB‐2 and JR‐2
Authors: Kasemann Simone , Meixner Anette , Rocholl Alexander , Vennemann Torsten , Rosner Martin , Schmitt Axel K. , Wiedenbeck Michael
Published: May 2007

We present data on the concentration, the isotope composition and the homogeneity of boron in NIST silicate glass reference materials SRM 610 and SRM 612, and in powders and glasses of geological reference materials JB‐2 (basalt) and JR‐2 (rhyolite). Our data are intended to serve as references for both microanalytical and wet‐chemical techniques. The δ11 B compositions determined by N‐TIMS and P‐TIMS agree within 0.5% and compare with SIMS data within 2.5%. SIMS profiles demonstrate boron isotope homogeneity to better than δ11 B = 2% for both NIST glasses, however a slight boron depletion was detected towards the outermost 200 μm of the rim of each sample wafer. The boron isotope compositions of SRM 610 and SRM 612 were indistinguishable. Glasses produced in this study by fusing JB‐2 and JR‐2 powder also showed good boron isotope homogeneity, both within and between different glass fragments. Their major element abundance as well as boron isotope compositions and concentrations were identical to those of the starting composition. Hence, reference materials (glasses) for the in situ measurement of boron isotopes can be produced from already well‐studied volcanic samples without significant isotope fractionation. Oxygen isotope ratios, both within and between wafers, of NIST reference glasses SRM 610 and SRM 612 are uniform. In contrast to boron, significant differences in oxygen isotope compositions were found between the two glasses, which may be due to the different amounts of trace element oxides added at ten‐fold different concentration levels to the silicate matrix.
The Use of Reference Materials: A Tutorial
Authors: Kane Jean S.
Published: May 2007

Any review of the analytical literature shows that, while reference materials are routinely used in laboratories world‐wide, not all uses follow ISO Guide 33 (1989), which outlines best practices. Analytical data quality can suffer as a result. This paper reviews the various uses that the geoanalytical community has made of reference materials from a historical perspective, and suggests improvements in practice that would more closely follow ISO Guide 33 recommendations.
Multiple Collector ICP‐MS: Introduction to Instrumentation, Measurement Techniques and Analytical Capabilities
Authors: Rehkämper Mark , Schönbächler Maria , Stirling Claudine H.
Published: May 2007

The technique of multiple collector ICP‐MS (MC‐ICP‐MS) has recently attracted much attention, because it permits the precise measurement of isotope compositions for a wide range of elements. This review article discusses the particular advantages of this mass spectrometric technique and provides an overview of the instrumentation. The performance characteristics of MC‐ICP‐MS instruments and procedures for the correction of instrumental mass discrimination are covered. The strategies that are employed to avoid analytical artefacts from spectral interferences and matrix effects are also considered. A range of applications are then discussed, to provide an overview of the versatility of this mass spectrometric technique. The diversity of applications, which include the measurement of radiogenic and stable isotope ratios, the determination of trace element concentrations by isotope dilution and in situ isotopic measurements using a laser ablation system, highlight the great relevance of MC‐ICP‐MS to present and future research in various Earth science disciplines.
On the Lu‐Hf Isotope Geochemistry of Silicate Rocks
Authors: Blichert‐Toft Janne
Published: May 2007

This paper reviews the history (TIMS, hot‐SIMS, MC‐ICP‐MS), significance, geochemical behaviour and current uncertainties (λ176 Lu, Hf‐Nd Bulk Silicate Earth) surrounding the Lu‐Hf isotope system, and thus marks two decades of its application to geochemical problems. An appendix further presents (a) improvements to the original chemistry protocol of Blichert‐Toft et al. (1997) for application to Mg‐rich samples and (b) a compilation of previously published and new Hf isotope determinations by MC‐ICP‐MS for a set of international rock reference materials.

Prior to the advent of multiple‐collector plasma source mass spectrometry (MC‐ICP‐MS), routine analysis of the Lu‐Hf isotope system developed only slowly because of the extreme difficulty of measuring Hf isotope compositions with thermal ionisation mass spectrometry, caused by the very high first ionisation potential of Hf. However, Hf isotope compositions can be measured relatively easily using MC‐ICP‐MS and this new technique now provides reproducible measurements at high precision regardless of the matrix from which Hf is separated.

Of the commonly used long‐lived radiogenic isotope systems, only the Sm‐Nd and Lu‐Hf isotope systems are unaffected by parent/daughter fractionations related to volatile nebular processes and core formation. While other systems (Rb‐Sr, U‐Th‐Pb, Re‐Os) may also be used to investigate the chemical evolution of the Earth, Moon, Mars and parent bodies of differentiated meteorites, the larger uncertainties in their bulk chemical and isotopic values limit their application to determine geochemical budgets and assess planetary mantle‐crust evolution. In the study of garnet‐bearing rocks, both for dating purposes and as an isotopic tracer for source provenance and mantle processes, the Lu‐Hf isotope system likewise is of major interest because of the high partition coefficient of Lu compared to Hf for garnet with respect to other minerals. Furthermore, the larger Lu/Hf fractionation compared to Sm/Nd during melting beneath ridges produces proportionally higher Lu/Hf in the residue and faster in‐growth of a radiogenic Hf isotopic signature (compared to Nd), which may help shed light on the dynamics of mantle melting.

While the chemistry protocol and mass spectrometric technique for high‐precision Lu‐Hf isotope analysis have been resolved in satisfactory ways over the past five years, more accurate determination of the decay constant for 176 Lu, at present known with a precision of only about 4%, still needs to be completed and a consensus reached on which value to use for future Lu‐Hf isotope studies. Although the current combined Lu‐Hf and Sm‐Nd Bulk Silicate Earth parameters are plagued by possible incompatibilities in chondrite selection and potential interlaboratory biases, a more accurate set of values may not be readily established owing to heterogeneities in the isotopic composition of chondrites that far exceed present analytical accuracy.
Reference Materials for Geochemical Studies: New Analytical Data by ICP‐MS and Critical Discussion of Reference Values
Authors: Dulski Peter
Published: May 2007

Abundances of twenty four trace elements, including Y and fourteen rare earth elements (REE), are reported for eighty six geological reference materials and four proficiency testing samples. Analytical data were obtained by ICP‐MS using solution nebulisation after mixed acid digestion (HF‐HClO4) under pressure. Analysed samples cover a wide range of element concentrations and mineralogical compositions, including samples for which there are few previously published data. Precision for elemental determinations in nearly 90% of the samples analysed is better than 5%. Accuracy, estimated by comparison with data from compilations is better than 6% for well characterized reference materials. Results obtained for samples that are low in trace elements are often significantly lower than compiled reference values. A critical discussion of the compiled data sets, especially for Y and the REEs, indicates that some reference values seem to be erroneous.
Determination of Total Sulfur in Thirty One Geochemical Reference Materials Using an Inductively Coupled Plasma‐Atomic Emission Spectrometer Fitted with a Semiconductor Photodiode Detector
Authors: Okai Takashi , Terashima Shigeru , Imai Noboru
Published: May 2007

The total sulfur contents of thirty one geochemical reference materials were determined using an inductively coupled plasma‐atomic emission spectrometer fitted with a semiconductor photodiode detector. Most samples were decomposed using an HF‐aqua regia digestion. However, a few were incompletely decomposed by simple acid digestion, and these were decomposed by a fusion method. The agreement between the analytical results from this work and published data is generally good.
Fitness‐for‐Purpose of Reference Material Reference Values in Relation to Traceability of Measurement, as Illustrated by USGS BCR‐1, NIST SRM 610 and IAEA NBS28
Authors: Kane Jean S.
Published: May 2007

As in all fields of sample analysis, reference materials play a large role in supporting measurements in the geosciences. While a rather large number of materials are in distribution (> 380), not all are equally effective or fit‐for‐purpose in supporting laboratory data quality and thereby assuring the desired comparability of measurements between laboratories. Equally important, reference values that are not fit‐for‐purpose cannot be used effectively to establish traceability links between laboratory measurements and national and international standards. The needed fitness‐for‐purpose is not achieved for reference values either when more than one reference value has been proposed and a consensus does not exist among users as to which should be used by all, or when reference value uncertainties are too large in comparison to those of routine laboratory measurements. The focus of this review will be, first to outline the current reality, and second to suggest ways in which certifications of RMs can be improved to provide reference values that are universally accepted and more fit‐for‐purpose in general laboratory use. The discussion will be illustrated largely by current uses of USGS BCR‐1, NIST SRM 610 and IAEA NBS28, as these three materials are those for which the largest body of newly published data exists, according to recent bibliographies of the geoanalytical literature published annually in Geostandards Newsletter: The Journal of Geostandards and Geoanalysis.
Trace Element Analysis of NIST SRM 614 and 616 Glass Reference Materials by Laser Ablation Microprobe‐Inductively Coupled Plasma‐Mass Spectrometry
Authors: Kurosawa Masanori , Jackson Simon E. , Sueno Shigeho
Published: May 2007

Fifty elements in NIST SRM 614 and 616 glass reference materials were determined by laser ablation microprobe‐inductively coupled plasma‐mass spectrometry (LAM‐ICP‐MS). The values determined for NIST SRM 614 agreed well with the NIST‐certified and information values (mean relative difference ± 3.6%), except for B, Sc and Sb. The values determined for NIST SRM 616 agreed with the NIST‐certified and information values within a mean relative difference of ± 1.5%, except for B, Sc and Ga. In addition, at an 80 μm sampling scale, NIST SRM 614 and 616 glass discs were homogeneous for trace elements within the observed precisions of 5 and 15% (mean), respectively. Detection limits were in the range 0.01 ‐ 0.3 μg g−1 for elements of lower mass numbers (amu < 80) and 1 ‐ 10 ng g−1 for heavy elements (amu > 80). Detection at the sub ng g−1 level is possible for most of the heavy elements by using an ablation pit size larger than 10 0 μm.
Trace Determination of Strontium and Barium in River Waters by Inductively Coupled Plasma‐Atomic Emission Spectrometry Using an Ultrasonic Nebulizer
Authors: Dalai Tarun K. , Sarin Manmohan
Published: May 2007

Inductively coupled plasma‐atomic emission spectrometry in conjunction with an ultrasonic nebulizer was employed for the determination of Sr and Ba in river waters at parts per billion (μg l−1) levels without pre‐concentration. The ultrasonic nebulizer, equipped with a desolvation system, enhanced the analytical sensitivity by ten to twenty fold compared to conventional pneumatic nebulizers. The detection limits for Sr and Ba, ascertained from blanks and reference samples made in 0.05% NaCl solution, were 0.045 μg l−1 and 0.16 μg l−1 respectively. The accuracy of measurements, based on analyses of solutions of reference materials (G‐2 and W‐1) and multielement commercial standards (Merck®), was ± 10%. Replicate analyses of samples and reference samples showed measurement precision to be to be better than ± 5%, which is adequate considering that the concentration of Sr and Ba in river waters varies by one to two orders of magnitude.
High Precision Hf‐W Isotopic Measurements in Meteoritic Material Using Negative Thermal Ionisation Mass Spectrometry (NTIMS)
Authors: Quitté Ghylaine , Birck Jean‐Louis , Capmas Françoise , Allègre Claude J.
Published: May 2007

This paper presents a two‐stage anion‐exchange procedure for tungsten extraction, an improved mass spectrometric procedure for tungsten analysis and a simplified chemical separation and TIMS procedure for the determination of Hf concentrations. The chemical separation of tungsten is based on its complexing properties with HF and H2O2. The blank level for a sample size of 300 mg is about 80 pg for tungsten. The procedure is designed for the high sensitivity of negative thermal ionisation mass spectrometry (NTIMS) provided by the use of Mg oxide as an emitter on Ir filaments. Tungsten can be readily measured with a high precision in various meteoritical material and especially in small W‐poor silicate fractions. Samples containing as little as a few ng g‐1 tungsten can be analysed reliably with this method.
A New Digestion and Chemical Separation Technique for Rapid and Highly Reproducible Determination of Lu/Hf and Hf Isotope Ratios in Geological Materials by MC‐ICP‐MS
Authors: Bizzarro Martin , Baker Joel A. , Ulfbeck David
Published: May 2007

A new digestion procedure and chemical separation technique has been developed for measurement of Lu/Hf and Hf isotope ratios that does not require high‐pressure bombs or use of HF or HClO4 acids. Samples are digested in dilute HCl or HNO3 after flux‐fusion at 110 0 °C in the presence of lithium metaborate. High field strength elements (HFSE) and rare earth elements (REE) are separated from this solution by co‐precipitation with iron hydroxide. The dissolved precipitate (in 2 mol l−1 HCl) is loaded directly onto a standard cation exchange column which separates remaining sample matrix from the heavy REE (Lu+Yb), and the middle‐light REE and HFSE (Hf). The middle‐light REE and individual HFSE are then separated (10.5, 9 and 6 mol l−1 HCl) using a miniaturized column containing TEVA spec resin which provides a REE‐, Ti‐ and Zr‐free Hf cut. This chemical separation scheme can also be readily adapted for isotopic analysis of the Sm‐Nd system and/or the other HFSE (Ti, Zr). Total procedural blanks for this technique are < 10 0 pg and < 2 pg for Hf and Lu, respectively, even when digesting large (0.5 g) samples.

We present data from replicate digestions of international rock reference materials which demonstrate this technique routinely reproduces Lu/Hf ratios to < 0.2% (2s) and 176 Hf/177 Hf isotope ratios to < 30 ppm (2s). Moreover, the technique is matrix‐independent and has been successfully applied to analysis of diverse materials including basalts, meteorites, komatiites, kimberlites and carbonatites. The relative simplicity of this technique, coupled with the ease of digestion (and sample‐spike equilibration) of large difficult‐to‐dissolve samples, and the speed (2 days) with which samples can be digested and processed through the chemical separation scheme makes it an attractive new method for preparing samples for Lu‐Hf isotopic investigation.
Determination of Halogens (F, Cl, Br, I), Sulfur and Water in Seventeen Geological Reference Materials
Authors: Michel Agnès , Villemant Benoît
Published: May 2007

Fluorine, chlorine, bromine, iodine and sulfur were determined in seventeen geological reference materials after extraction by pyrohydrolysis. Fluorine, Cl and S (as sulfate ions) were determined in the extraction solution by ion chromatography with detection limits of around 0.2 mg l−1. Bromine and I were measured by ICP‐MS with detection limits of 1 μg l−1 for Br and 0.1 μg l−1 for I. For rock samples, using normal extraction conditions (500 mg of sample and 100 ml of final solution) detection limits were 40 mg kg−1 for F and Cl, 15 mg kg−1 for S, 0.2 mg kg−1 for Br and 0.02 mg kg−1 for I. These detection limits may be improved by increasing the amount of sample and hence the concentration of the final solution. Water was also determined using an extraction technique based on H2O degassing, reduction on zinc at 1000 °C and H2 manometry. Our results for fluorine, chlorine, sulfur and water are in good agreement with literature data. Very few reference materials have recommended values for bromine and especially for iodine. Among the analysed samples, three are new reference materials: BHVO‐2, BCR‐2 and AGV‐2.
Neodymium and Strontium Isotope Data for USGS Reference Materials BCR‐1, BCR‐2, BHVO‐1, BHVO‐2, AGV‐1, AGV‐2, GSP‐1, GSP‐2 and Eight MPI‐DING Reference Glasses
Authors: Raczek Ingrid , Jochum Klaus Peter , Hofmann Albrecht W.
Published: May 2007

We have measured 87Sr/86Sr and 143 Nd/144 Nd isotope ratios in different batches and aliquots of the new US Geological Survey (USGS) reference materials (RMs) BCR‐2, BHVO‐2, AGV‐2 and GSP‐2 and the original USGS RMs BCR‐1, BHVO‐1, AGV‐1 and GSP‐1 by thermal ionisation mass spectrometry. In addition, we also analysed the eight Max‐Planck‐Institut‐Dingwell (MPI‐DING) reference glasses. Nearly all isotope ratios obtained in the different aliquots and batches agree within uncertainty limits indicating excellent homogeneity of the USGS powders and the MPI‐DING glasses. With the exception of GSP‐2, the new USGS RMs are also indistinguishable from the ratios found in the original USGS RMs (87Sr/86Sr: 0.704960, 0.704958 (BCR‐1, ‐2), 0.703436, 0.703435 (BHVO‐1, ‐2), 0.703931, 0.703931 (AGV‐1, ‐2); 143 Nd/144 Nd: 0.512629, 0.512633 (BCR‐1, ‐2), 0.512957, 0.512957 (BHVO‐1, ‐2); 0.512758, 0.512755 (AGV‐1, ‐2)). This means that for normalisation purposes in Sr and Nd isotope geochemistry BCR‐2, BHVO‐2 and AGV‐2 can well replace BCR‐1, BHVO‐1 and AGV‐1 respectively.
Certified Reference Materials of Copper, Lead and Zinc (Silver) Ore Rocks and Their Concentrates (GSO 1‐7)
Authors: Gu Tiexin , Bu Wei , Yan Weidong , Shi Changyi , Yan Mingcai
Published: May 2007

Sulfide mineral certified reference materials GSO 1‐7, recently prepared by the Institute of Geophysical and Geochemical Exploration (IGGE), were analysed by twelve laboratories. Various reliable analytical methods based on different principles were adopted and classical chemical methods were taken as the primary analytical methods, by which 5729 determinations were carried out, 1425 average data were obtained, and twenty one to twenty seven elements and components were certified.
New Series of Soil Geochemical Reference Materials (GSS 10‐16) from the Main Overburden Region in China
Authors: Gu Tiexin , Bu Wei , Yan Weidong , Shi Changyi , Yan Mingcai
Published: May 2007

Seven soil geochemical certified reference materials (CRMs) GSS 10‐16 recently prepared by the Institute of Geophysical and Geochemical Exploration (IGGE), are mainly used for sample analysis in geochemical surveys of the overburden region in China. Fifteen Chinese institutes and central laboratories, which operated at a high level of analytical performance analysed these samples. More than ten reliable analytical methods based on different principles of measurement were adopted, of which ICP‐MS, ICP‐AES and NAA were taken as the primary analytical methods. In total, 23715 determinations were carried out, 5660 average data sets were obtained, seventy two elements and components were determined and certified values of sixty nine elements and components were assigned. Rhenium concentrations were measured by isotope dilution ICP‐MS in GSS‐10, GSS‐13, GSS‐15 and GSS‐16. Certified values of elements in GSS 10‐16 have good precision and for 90% of these values relative uncertainties are less than 10%.
Calcium Isotopic Composition of Various Reference Materials and Seawater
Authors: Hippler Dorothee , Schmitt Anne‐Désirée , Gussone Nikolaus , Heuser Alexander , Stille Peter , Eisenhauer Anton , Nägler Thomas F.
Published: May 2007

A compilation of δ44/40Ca (δ44/40Ca) data sets of different calcium reference materials is presented, based on measurements in three different laboratories (Institute of Geological Sciences, Bern; Centre de Géochimie de la Surface, Strasbourg; GEOMAR, Kiel) to support the establishment of a calcium isotope reference standard. Samples include a series of international and internal Ca reference materials, including NIST SRM 915a, seawater, two calcium carbonates and a CaF2 reference sample. The deviations in δ44/40Ca for selected pairs of reference samples have been defined and are consistent within statistical uncertainties in all three laboratories. Emphasis has been placed on characterising both NIST SRM 915a as an internationally available high purity Ca reference sample and seawater as representative of an important and widely available geological reservoir. The difference between δ44/40Ca of NIST SRM 915a and seawater is defined as ‐1.88 O.O4%o (δ44/42CaNISTSRM915a/Sw= ‐0.94 0.07%o). The conversion of values referenced to NIST SRM 915a to seawater can be described by the simplified equation δ44/40CaSa/Sw=δ44/40CaSa/NIST SRM 915a ‐ 1.88 (δ44/42CaSa/Sw=δ44/42CaSa/NIST SRM 915a ‐ 0.94). We propose the use of NIST SRM 915a as general Ca isotope reference standard, with seawater being defined as the major reservoir with respect to oceanographic studies.
Intercomparison of Boron Isotope and Concentration Measurements. Part I: Selection, Preparation and Homogeneity Tests of the Intercomparison Materials
Authors: Tonarini Sonia , Pennisi Maddalena , Adorni‐Braccesi Alessandra , Dini Andrea , Ferrara Giorgio , Gonfiantini Roberto , Wiedenbeck Michael , Gröning Manfred
Published: May 2007

In 1999 the Istituto di Geoscienze e Georisorse (IGG), with the support of the International Atomic Energy Agency (IAEA), undertook the collection, preparation and distribution of eight geological materials intended for a blind interlaboratory comparison of measurements of boron isotopic composition and concentration. The materials came from Italian sources and consist of three natural waters (Mediterranean seawater and two groundwaters) and five rocks and minerals (tourmaline, basalt, obsidian, limestone and clay). The solid materials were crushed, milled and mixed, in preparation for distribution. Extensive assays performed at the IGG on these materials demonstrated that their boron isotopic and chemical compositions are homogeneous.

Additional homogeneity tests were carried out on solid material fragments at the GeoForschungsZentrum Potsdam, with the specific objective of investigating the suitability of some of them for the calibration in situ of micro‐analytical techniques. Two materials, B4 (tourmaline) and B6 (obsidian), proved to be isotopically homogeneous and may become excellent references for in situ microanalyses of boron isotopes.

The materials described here were used as the basis of a major laboratory intercomparison study and are now available for further distribution from either the IAEA (solid materials) or the IGG (waters).
Major and Trace Element Analysis of Silicate Rocks by XRF and Laser Ablation ICP‐MS Using Lithium Borate Fused Glasses: Matrix Effects, Instrument Response and Results for International Reference Materials
Authors: Yu Zongshou , Norman Marc D. , Robinson Philip
Published: May 2007

Major and trace element compositions of fifteen silicate rock reference materials have been determined by a combined XRF and laser ablation ICP‐MS (LA‐ICP‐MS) technique on glasses prepared by fusing the sample with a lithium borate flux (sample:flux = 1:3). Advantages of this technique include the ability to measure major and trace element abundances on a single sample using a quick and simple preparation that attacks resistant phases such as zircon without the need for acid dissolution. The method is suitable for a wide variety of bulk compositions including mafic, intermediate and silicic rocks.

Abundance‐normalized mass response patterns (the ratio of signal intensity to element concentration) of the LA‐ICP‐MS analyses vary systematically with major element composition, demonstrating the presence of a matrix effect that cannot be compensated by normalisation to a single internal standard element. Increasing the sampling distance between the ICP‐MS cone and the torch reduces the magnitude of this effect, suggesting that a mechanism related to residence time of ablated particles in the plasma may be at least partially responsible for the observed variations in mass response patterns. When using a matrix‐matched calibration, agreement of the LA‐ICP‐MS results with published reference values or those obtained by solution ICP‐MS is 10% relative. Analytical precision based on replicate analyses is typically 5% RSD. Procedural detection limits that include contributions from gas background and flux are 0.01‐0.1 μg g‐1 for the heavy mass trace elements (Rb‐U). Major element analyses by XRF show excellent agreement with results obtained using a conventional heavy element absorbing flux. High quality major and trace element data for silicate rocks can be achieved by a combined XRF and LA‐ICP‐MS analysis of Li2B4O7/LiBO2 fused glasses provided an appropriate matrix‐matched calibration is adopted.
Determination of Gold in Ores by Isobutyl Methyl Ketone Extraction and Electrothermal Atomic Absorption Spectrometry: A Stability Study of the Metal in Organic Media
Authors: Monteiro Maria Inês C. , Lavatori Marcos Paulo A. , de Oliveira Nilza Maria M.
Published: May 2007

A method involving gold extraction into isobutyl methyl ketone (IBMK), after partial dissolution with aqua regia, with determination by electrothermal atomic absorption spectrometry is described. The pyrolysis and atomisation temperatures were optimized using a pyrolytic graphite forked platform. The stability study of gold in isobutyl methyl ketone extract indicated that closed polypropylene containers (3% absorbance measurement changes) were better than both open polypropylene and closed glass containers over periods of up to 22 hr. Satisfactory recoveries of 99 and 102% were obtained when Au, in the IBMK extracts from CH‐3 and MA‐2 reference materials, were determined after storage of the extracts in closed polypropylene containers for 22 hr, respectively.
Concentrations of Trace Elements in Carbonate Reference Materials Coral JCp‐1 and Giant Clam JCt‐1 by Inductively Coupled Plasma‐Mass Spectrometry
Authors: Inoue Mayuri , Nohara Masato , Okai Takashi , Suzuki Atsushi , Kawahata Hodaka
Published: May 2007

Trace elements in the Geological Survey of Japan carbonate reference materials Coral JCp‐1 and Giant Clam JCt‐1 were determined by inductively coupled plasma‐mass spectrometry after digestion with 2% v/v HNO3. A standard addition method was adopted in this determination in order to neutralise the Ca matrix effect. In addition, Sc, Y, In and Bi were used as internal standards to control the matrix effect and correct instrumental drift. Of the eighteen elements measured in JCp‐1, precisions for fourteen elements, including Cu, Cd and Ba, were better than 10% RSD and concentrations ranged from 0.002 μg g‐1 (Cs) to 8.02 μg g‐1 (Ba). The concentrations of measured trace elements in JCt‐1, except for Cu, were lower than those in JCp‐1. Precisions for all elements with concentrations higher than 0.04 μg g‐1 in JCt‐1 were also better than 10% RSD and concentrations were found to be between 0.001 μg g‐1 (Cs) and 4.84 μg g‐1 (Ba). The concentrations of more than fifteen trace elements in the aragonite reference materials are reported here for the first time. Both reference materials are suitable for use in geochemical studies of environmental reconstruction based upon biogenic carbonate materials.
Isotope Dilution MC‐ICP‐MS Rare Earth Element Analysis of Geochemical Reference Materials NIST SRM 610, NIST SRM 612, NIST SRM 614, BHVO‐2G, BHVO‐2, BCR‐2G, JB‐2, WS‐E, W‐2, AGV‐1 and AGV‐2
Authors: Kent Adam J.R. , Jacobsen Benjamin , Peate David W. , Waight Tod E. , Baker Joel A.
Published: May 2007

We present data for the concentrations of eleven rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er, Yb, Lu) in eleven international geochemical reference materials obtained by isotope dilution multi‐collector inductively coupled plasma‐mass spectrometry (MC‐ICP‐MS). We have analysed both rock powders and synthetic silicate glasses, and the latter provide precise data to support the use of these as reference materials for in situ trace element determination techniques. Our data also provide precise measurements of the abundance of mono‐isotopic Pr in both glasses and powders, which allows more accurate constraints on the anomalous redox‐related behaviour of Ce during geochemical processes. All materials were analysed in replicate providing data that typically reproduce to better than one percent. Sm/Nd ratios in all these materials also reproduce to better than 0.2% and are accurate to < 0.2% and can thus be used as calibrants for Sm‐Nd geochronology. Our analyses agree well with existing data on these reference materials. In particular, for NIST SRM 610, USGS BHVO‐2, AGV‐1 and AGV‐2, our measured REE abundances are typically within < 2% (and mostly 1%) of REE concentrations previously determined by isotope dilution analysis and thermal ionisation mass spectrometry, consistent with the higher degree of precision and accuracy obtained from isotope dilution techniques. Close agreement of results between basaltic glass reference materials USGS BHVO‐2G and BCR‐2G and the BHVO‐2 and BCR‐2 powders from which they were created suggests that little fractionation, concentration or dilution of REE contents occurred during glass manufacture.