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1.
Two Re-Os dating reference material molybdenites were prepared. Molybdenite JDC and molybdenite HLP are from a carbonate vein-type molybdenum-(lead)-uranium deposit in the Jinduicheng-Huanglongpu area of Shaanxi province, China. The samples proved to be homogeneous, based on the coefficient of variation of analytical results and an analysis of variance test. The sampling weight was 0.1 g for JDC and 0.025 g for HLP. An isotope dilution method was used for the determination of Re and Os. Sample decomposition and pre-concentration of Re and Os prior to measurement were accomplished using a variety of methods: acid digestion, alkali fusion, ion exchange and solvent extraction. Negative thermal ionisation mass spectrometry and inductively coupled plasma-mass spectrometry were used for the determination of Re and 187Os concentration and isotope ratios. The certified values include the contents of Re and Os and the model ages. For HLP, the Re content was 283.8 ± 6.2 μg g−1, 187Os was 659 ± 14 ng g−1 and the Re-Os model age was 221.4 ± 5.6 Ma. For JDC, the Re content was 17.39 ± 0.32 μg g−1, 187Os was 25.46 ± 0.60 ng g−1 and the Re-Os model age was 139.6 ± 3.8 Ma. Uncertainties for both certified reference materials are stated at the 95% level of confidence. Three laboratories (from three countries: PR. China, USA, Sweden) joined in the certification programme. These certified reference materials are primarily useful for Re-Os dating of molybdenite, sulfides, black shale, etc.  相似文献   

2.
Six low abundance rock reference materials (basalt BIR-1, dunite DTS-1, dolerite DNC-1, peridotite PCC-1, serpentine UB-N and basalt TAFAHI) have been analysed for high field strength elements (Zr, Nb, Hf, Ta, Th and U), Rb, Sr, Mo, Sb, Cs, Tl and Bi at ng g−1 levels (in rock) by magnetic sector inductively coupled plasma-mass spectrometry after HF/HClO4 high pressure decomposition. The adopted method uses only indium as an internal standard. Detection limits were found to be in the range of 0.08 to 16.2 pg ml−1 in solution (equivalent to 0.08 to 16.2 ng g−1 in rock). Our data for high field strength elements, Rb, Sr, Mo, Sb, Cs, Tl and Bi for the six selected low abundance geological reference materials show general agreement with previously published data. Our Ta values in DTS-1 and PCC-1 (1.3 and 0.5 ng g−1) are lower than in previously published studies, providing smooth primitive mantle distribution patterns. Lower values were also found for Tl in BIR-1, DTS-1 and PCC-1 (2, 0.4 and 0.8 ng g−1). Compared with quadrupole ICP-MS studies, the proposed magnetic sector ICP-MS method can generally provide better detection limits, so that the measurement of high field strength elements, Rb, Sr, Mo, Sb, Cs, Tl and Bi at ng g−1 levels can be achieved without pre-concentration, ion exchange separation or other specialised techniques.  相似文献   

3.
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.  相似文献   

4.
Fifty-two trace elements in NIST SRM 614, 616 and MPI-DING BM90/21-G glass reference materials as well as in NIST SRM 612, USGS BCR2-G and other MPI-DING reference glasses (KL2-G, GOR132-G, GOR128-G, ATHO-G, Tl-G, StHs6/80-G and ML3B-G) were determined by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Accurate ultra-low trace element abundances in the NIST SRM 614, 616 and BM90/21-G reference glasses down to lower ng g−1 levels were determined with relative standard deviations (RSD) of less than 10%. Limits of detection using He as carrier gas were up to two times lower than with Ar and were 0.004 to 0.12 μg g−1 for elements of lower mass numbers (amu < 85) and 0.002 to 0.06 μg g−1 for elements having amu < 85. The measured concentrations generally agree within 15% with previous studies except for B in NIST SRM 614 and 616, which appears to be heterogeneously distributed, and Co, Zn, Ga and Ag in NIST SRM 616 for which the existing data set is too small to evaluate the discrepancies. New values for As (0.593 μg g−1), Ag (0.361 μg g−1) and Cd (0.566 μg g−1) in NIST SRM 614 and new values for Na (94864 μg g−1) and As (0.276 μg g−1) in NIST SRM 616 are reported.  相似文献   

5.
New sample preparation and ion-exchange separation methods as well as instrumental measurement protocols were established for the determination of trace-level Cd, In, and Te concentrations in geological materials by isotope-dilution mass spectrometry. High precision isotope ratio measurements were performed with a multiple collector inductively coupled plasma-mass spectrometer (MC-ICP-MS). The mass biases incurred for In and Te were corrected by adding and monitoring Pd and Sb standard solutions, respectively. Mass fractionation of Cd was corrected by using the mass fractionation factor calculated from the measurement of a standard solution. The measurement precision was better than 1 % for Cd, In and Te. Detection limits were < 1 ng g-1 for Cd, < 0.02 ng g-1 for In and Te. Using these new analytical techniques, the concentrations of Cd, In and Te were determined in six international geological reference materials. Concentrations could be reproduced within 3% for Cd, 4% for In and 10% for Te. Sample heterogeneity and volatility problems might have been the reason for the relatively large differences between Te replicates. Our results displayed excellent reproducibility compared with those of other techniques and agree well with data from previously published recommended values.  相似文献   

6.
We present a revised method for the determination of concentrations of rare earth (REE) and other trace elements (Y, Sc, Zr, Ba, Hf, Th) in geological samples. Our analytical procedure involves sample digestion using alkaline fusion (NaOH-Na2O2) after addition of a Tm spike, co-precipitation on iron hydroxides, and measurement by sector field-inductively coupled plasma-mass spectrometry (SF-ICP-MS). The procedure was tested successfully for various rock types (i.e., basalt, ultramafic rock, sediment, soil, granite), including rocks with low trace element abundances (sub ng g−1). Results obtained for a series of nine geological reference materials (BIR-1, BCR-2, UB-N, JP-1, AC-E, MA-N, MAG-1, GSMS-2, GSS-4) are in reasonable agreement with published working values.  相似文献   

7.
Inductively coupled plasma-mass spectrometry is well suited for the precise, accurate and rapid determination of rare earth elements in most geological samples. However, determination of rare earth elements in certain mantle-derived materials, without applying preconcentration techniques, remains problematical due to low natural concentrations (generally < 1 ng g−1). Consequently, USGS reference materials DTS-1 (a dunite) and PCC-1 (a partially serpentinized harzburgite) have only suggested rather than recommended values for the rare earth elements in reference material compilations. We compared results obtained using two ICP-MS instruments: a U-5000AT ultrasonic nebuliser coupled to a PQ2+ quadrupole ICP-MS and an ELEMENT sector field ICP-MS equipped with a MCN-6000 microconcentric desolvating nebuliser, with the suggested literature values for these two reference materials. Precision and accuracy of analytical methods employed by both instruments were demonstrated by excellent relative standard deviations (< 2%) and inter-laboratory agreement (< 5%) for numerous analyses of BHVO-1 and BIR-1, which are well established with rare earth elements contents at the μg g−1 level. Repeat analyses of DTS-1 and PCC-1 at each laboratory indicate that each method is generally precise to better than 5% at sub-g g−1 levels. Furthermore, values from both instruments generally agree to within 10%. Our DTS-1 and PCC-1 values agree reasonably well with selected data reported in the literature (except for Ce and Sm in DTS-1) but exhibit poorer agreement with reported compilation values. With the demonstrated level of precision and accuracy, we contend that these new values for DTS-1 and PCC-1, generated by two different instruments, are the best estimates of the true whole-rock composition of these samples reported to date.  相似文献   

8.
A method for the selective separation of Ag, Cd, Cr, Cu, Ni, Pb and Zn in traces from solutions of calcite (CaCO3), dolomite (CaMg(CO3)2) and gypsum (CaSO4.2H2O) before their determination by inductively coupled plasma-atomic emission spectrometry (ICP-AES) is presented. The expected interferences of Ca and Mg on intensities of trace analytes were removed by collecting the elements of interest with cobalt(III) hexamethylenedithiocar-bamate, Co(HMDTC)3. The flotation of aqueous solutions (1 l) of calcite, dolomite and gypsum was performed at pH 6.0, by 1.5 mg l−1 Co and 0.6 mmol l−1 HMDTC−. To minimise the effect of the reaction between Ca/Mg, which restrains the function of the surfactant, careful selection of the most suitable foaming reagent was necessary. The accuracy of the method was established by analysing natural alkaline-earth minerals by the standard addition method as well as using the dolomite reference materials GBW 07114 and GSJ JDo-1. The ICP-AES limits of detection following flotation on different minerals were found to be 0.080 μg g−1 for Cd, 0.105 μg g−1 for Ag, 0.142 μg g−1 for Cu, 0.195 μg g−1 for Cr, 0.212 μg g−1 for Ni, 0.235 μg g−1 for Zn and 0.450 μg g−1 for Pb.  相似文献   

9.
A combination of EMPA, sensitive high resolution ion microprobe (SHRIMP II) and/or LA-ICP-MS techniques was used to measure the concentration of selenium (Se) in NIST SRM 610, 612, 614 and a range of reference materials. Our new compiled value for the concentration of Se in NIST SRM 610 is 112 ± 2 μg g−1. The concentration of Se in NIST SRM 612, using NIST SRM 610 for calibration, determined using LA-ICP-MS (confirmed using SHRIMP II) was 15.2 ± 0.2 μg g−1. The concentration of Se in NIST SRM 614, using LA-ICP-MS was 0.394 ± 0.012 μg g−1. LA-ICP-MS determination of Se in synthetic geological glasses BCR-2G, BIR-1G, TB-1G and the MPI-DING glasses showed a range in concentrations from 0.062 to 0.168 μg g−1. Selenium in the natural glass, VG2, was 0.204 ± 0.028 μg g−1.  相似文献   

10.
The concentration of boron was determined in twenty one geochemical reference materials (silicate rocks) by isotope dilution inductively coupled plasma-mass spectrometry. Boron was extracted from the rocks using HF digestion, suppressing boron volatilisation through boron-mannitol complexation. Sample solutions, in a diluted HCl matrix, were analysed by ICP-MS without any separation of boron from the matrix elements. The results obtained were in agreement with the literature data and indicate that using the described procedure, trace amounts of boron can be very easily determined in complex matrices with rapidity and precision. With the instrumentation and reagents used in this study, this procedure can be used for the determination of 0.5 μg g−1 boron in a 15 0 mg silicate rock sample. Replicate analyses of the twenty one geochemical reference materials (GRM), ranging in boron concentration from 1.35 to 15 7 μg g−1, yielded precisions (relative standard deviation) varying between 0.9 and 9.8%.  相似文献   

11.
A method for the determination of Ge, As, Se and Te in silicate samples using isotope dilution-internal standardisation (ID-IS) octopole reaction cell (ORC) ICP-QMS by normal sample nebulisation was developed. The method does not involve either hydride generation or ion exchange. Germanium, Se and Te were determined by isotope dilution (ID), and As was determined by ID-IS. A silicate sample with an added Ge-Se-Te spike was digested with an HF-HNO3-HBr mixture, dried, re-dissolved with HF and the supernatant liquid was directly aspirated into an ORC-ICP-QMS instrument with He or H2 gas. No matrix effects were observed down to a dilution factor (DF) of ∼ 70 for Ge, Se and Te and DF of ∼ 1000 for As, which resulted in 3s detection limits in silicates of 2, 1, 0.1 and 4 ng g−1, respectively. Advantages of the method are the simple sample introduction as well as a capability of determining S, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta by ID-IS-ICP-QMS/SFMS from the same solution. Furthermore, the total sample solution consumption was only 0.253 ml with DF = 2000. Therefore, only a 0.13 mg test portion was required. To demonstrate the applicability of this technique, Ge, As, Se and Te in eight silicate reference materials were determined, as well as S, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta in four carbonaceous chondrites.  相似文献   

12.
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%.  相似文献   

13.
Inductively coupled plasma-mass spectrometry (ICP-MS) after NiS fire assay-Te co-precipitation was employed in the determination of Ru, Rh, Pd, Os, Ir and Pt at ng g-1 levels in six platinum-group element (PGE) geological reference materials. In general, the average of several results was in good agreement with the certified values taking into account respective uncertainties. High relative standard deviations were observed for the reference materials GPt-3 and GPt-4. Problems associated with the NiS fire assay procedure and PGE determination at the sub-10 ng g-1 level are reviewed and discussed.  相似文献   

14.
Selenium has been determined in sixty five geological reference materials of different origins by graphite furnace atomic absorption spectrometry. Samples were decomposed with a mixture of nitric and hydrofluoric acids. Selenium was reduced to SeIV with hydrochloric acid, and then fixed and separated from the matrix on thiol cotton. After digestion of the thiol cotton in hot nitric acid, the Se concentration was measured using palladium and magnesium nitrates as a matrix modifier. The limit of determination was 0.02 μg g−1, the precision of the results (relative standard deviation of 3 to 8 replicates) varied from 2.6 to 17.7% with an average of 7.9% in the range 0.02-42.7 μg g−1 and was similar to the value obtained for synthetic samples. Our results are in good agreement with available literature values.  相似文献   

15.
The direct analysis of nickel sulfide fire assay buttons by UV laser ablation ICP-MS was used to determine the platinum-group elements and gold in the following reference materials: UMT-1, WPR-1, WMG-1, GPt-4, GPt-6 and CHR-Bkg. The instrument was calibrated with buttons prepared using quartz doped with the appropriate standard solutions. Analytical precision (RSD) was generally better than 10%, although occasional higher RSDs may infer local heterogeneities within nickel sulfide buttons. Good or excellent agreement was observed between analysed and reference material values except Rh in UMT-1 and WMG-1, which suffered an interference from copper. Detection limits calculated as 10 s quantitation limits were Au (1.7 ng g−1), Pd (3.3 ng g−1), Pt (8.3 ng g−1), Os (1.3 ng g−1), Rh (1 ng g−1), Ru (5 ng g−1) and Ir (0.7 ng g−1).  相似文献   

16.
We have developed a rapid and accurate method for the determination of Mo, Sb and W in geological samples using isotope dilution inductively coupled plasma-mass spectrometry with a flow injection system (ID-FI-ICP-MS). The chemical procedure requires HF digestion of the sample with a Mo-Sb-W mixed spike, subsequent evaporation and dissolution of Mo, Sb and W from Mg and Ca fluorides with HF. Recovery yields of Mo, Sb and W in the extraction were > 94% for samples of peridotite, basalt and andesite composition, with the exception of W in samples of peridotite composition for which recovery was 81%. No matrix effects were observed in the determination of the isotope ratios of Mo, Sb and W in solutions prepared from peridotite, basalt and andesite samples down to a dilution factor of 100. Detection limits of Mo, Sb and W in silicate materials were at the several ng g−1 level. Analysis of the silicate reference materials PCC-1, DTS-1, BCR-1, BHVO-1, AGV-1 from the US Geological Survey and JP-1, JB-1, -2, -3, JA-1, -2, and -3 from the Geological Survey of Japan as well as the Smithsonian reference Allende powder yielded reliable Mo, Sb and W concentrations. The repeatability in the analysis of basalts and andesites was < 9%. This technique requires only 0.2 ml sample solution, and is therefore suitable for analyzing small and/or precious samples such as meteorites, mantle peridotites and their mineral separates.  相似文献   

17.
The platinum-group elements (PGE) and gold have been determined in twenty international rock reference materials by inductively coupled plasma-mass spectrometry (ICP-MS) after pre-concentration by a nickel sulfide fire assay. It was possible to achieve determination limits for a 50 g sample that ranged from 1 pg g-1 (Rh) to 23 pg g-1 (Au). Compared to published certified and recommended values for rock reference materials, the trueness of the method was found to be good. However, in some cases we observed large deviations for all elements in the sub 10 ng g-1 range within individual reference sample splits. Our results show that the PGE and Au are inhomogeneously distributed in the reference materials analysed here, where they are present in low concentrations, using 50 g test portions.  相似文献   

18.
The high sensitivity, minimal oxide formation and single internal standard capability of high resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS) is demonstrated in the direct determination of Sc, Y and REE in the international reference materials: basalts (BCR-1, BHVO-1, BIR-1, DNC-1), andesite (AGV-1) andultramafics (UB-N, PCC-1 and DTS-1). Time consuming ion exchange separation or preconcentration were found to be unnecessary. Smooth chondrite normalized plots of the REE in PCC-1 and DTS-1 were obtained in the range 0.8-50 ng g-1 (0.01-0.1x chondrite). Method precision was found to be digestion dependent with an average external repeatability of 2-4% for the basalts, AGV-1 and UB-N, and 10% for PCC-1 and DTS-1. The mass peak due to 45Sc was completely resolved from 29Si16O and 28Si16O1H spectral interferences using medium resolution, which casts doubt on the accuracy of Sc determinations using quadrupole ICP-MS. Literature values for Y in rock reference materials were found to be approximately 9% high after HR-ICP-MS and XRF analysis.  相似文献   

19.
The microanalytical capability of laser ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS) to determine ultra trace elemental concentrations has been demonstrated by the analysis of two low concentration glass standard reference materials, NIST SRM 614 and 616. Results for fifty two elements at concentrations in the low ng g-1 range are compared with those determined using secondary ion mass spectrometry (SIMS). Both techniques provide results at these concentrations that generally agree within 95% confidence limits, demonstrating the accuracy for ultra-trace level of in situ determinations by the two techniques. At concentrations of less than 20 ng g-1 in NIST SRM 616, an accuracy and precision of better than 10% has been obtained for most mono-isotopic rare earth elements, when a spot size of 50 μm is used. Limits of detection for selected elements were as low as 0.5 ng g-1.  相似文献   

20.
Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is a microanalytical tool especially suitable for providing fast and precise U-Pb geochronological results on zircon grains. A new 193 nm excimer laser adapted to a micromachining workstation, equipped with a newly designed two-volume ablation cell and coupled with a quadrupole ICP-MS, is presented here. The system was tuned routinely to achieve sensitivities in the range of 3000 cps/μg g−1 for 238U (< 2% RSD), with a 34 μm spot size, at 5 Hz and ∼ 8 J cm−2, while ablating the NIST SRM 612 glass reference material. The system was capable of providing fast (< 1.5 minutes each analysis) and precise (generally < 1.5% 1s errors) 206Pb/238U zircon ages. The ages of widely used reference material zircons (Plesovice, 337 Ma; Temora, 416 Ma; R33, 418 Ma; Sri Lanka, 564 Ma; 91500, 1065 Ma) could be precisely matched, with an accuracy on isotopic ratios that ranged from ∼ 2 to ∼ 6%, depending on the homogeneity of the natural reference materials.  相似文献   

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