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1.
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   

2.
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   

3.
Total sulfur is an analyte for which there are few determinations published, despite the fact that it is a very important element (e.g., a major element in most ores, an important gas constituent in global warming, an active participant in acid drainage). Most geological reference materials have very poor quality sulfur results, that is with relative standard deviations (RSD) in the range of 30–50%, even for concentrations over 100 μg g−1 S, which compromises their use as calibrators. In order to provide modern results with low RSD, sulfur was determined in twenty-nine geological reference materials with a state-of-the-art elemental S/C analyser using metal chips (certified reference materials with a traceability link) and analytical grade sulfur for high concentration samples. Analytical parameters (sample mass, crucible degassing, calibration strategy, etc.) were optimised by testing. Our results agreed with reference material values provided by issuing bodies. Results for CCRMP SY-2 (129 ± 13 μg g−1 S), which has been proposed as a sulfur reference material, were in agreement with the proposed modern value of 122 ± 3.7 μg g−1 S.  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.
Promising methods have been developed recently for the determination of selenium (Se) and tellurium (Te) in geological materials at ng g−1 and lower levels, using hydride generation-inductively coupled plasma-mass spectrometry. Here we report on a new isotope dilution-hydride generation-inductively coupled plasma-mass spectrometry (ID-HG-ICP-MS) method for the simultaneous determination of Se and Te, which is applied to basalts, and modified compared to previous work. The basalts were attacked and dissolved with hydrofluoric and nitric acid, spiked with enriched isotopes, and passed through a cation exchange column (AG 50-X8 100–200 mesh) to separate the major cations that interfere with Se and Te detection (e.g., Fe). The detection limits of this method were 0.010 ng g−1 for Se and 0.0030 ng g−1 for Te, well below the concentrations of Se and Te expected in basalts. The precision of the method for Se was 12.2 to 15.1% and for Te was 4.6 to 7.2% RSD from replicate analyses of basalt reference samples. The accuracy for Se determinations was 61 to 94% and for Te 28 to 100% of values previously reported in the literature for selected USGS reference materials.  相似文献   

6.
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   

7.
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   

8.
We report new data on the trace element concentrations of Mg, Cr, Mn, Co, Ni, Cu, Zn, Sr, Cd, Ba, La, Ce, Nd, Pb and U in USGS carbonate reference materials (MACS-1 and MACS-2) and compare solution ICP-MS and LA-ICP-MS trace element determinations on landfill calcites using calibration to different reference materials (MACS-1 and MACS-2 carbonate and NIST SRM 612 glass). Very good agreement (differences below 10% relative) was found between laser ablation and solution ICP-MS data for MACS-1 with higher concentrations of trace elements (values between 100 and 150 μg g−1), with the exception of Cu and Zn. Similarly good agreement was found for MACS-2 with lower trace element concentrations (units to tens of μg g−1), with the exception of Cr, Co and Zn. The MACS-1 reference material for calibration of LA-ICP-MS was found to be extremely useful for in situ determination of trace elements in real-world carbonate samples (landfill calcites), especially those present in calcite in higher concentrations (Mn, Sr, Ba; < 5% RSD). Less accurate determinations were generally obtained for trace elements present at low concentrations (∼ units of μg g−1). In addition, good agreement was observed between the instrument calibration to MACS and NIST SRM 612 glass for in situ measurements of trace elements in landfill calcites K-2, K-3 and K-4 (differences below 15% relative for most elements). Thus, the application of MACS carbonate reference materials is promising and points to the need for the development of new carbonate reference materials for laser ablation ICP-MS.  相似文献   

9.
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   

10.
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   

11.
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   

12.
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.  相似文献   

13.
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   

14.
The analysis of granitic pegmatites still remains a challenge because suitable natural reference materials are scarce or not available. Two new reference materials were prepared at the Smithsonian Institution, to provide an avenue to pursue the geochemical analysis of micas and feldspars in granitic pegmatites: STL-1, the Stewart lepidolite (NMNH 174041) and ZA-1, the Zapot amazonite (NMNH 174042). STL-1 was prepared from lepidolite collected from the lithium-rich Stewart pegmatite, San Diego County, California (33°22'52'N, 117°03'41'W). ZA-1 was prepared from an amazonite from the topaz-bearing Zapot pegmatite, Mineral County, Nevada, (38° 41'N, 118 °33'W). The results of this study indicated that STL-1 and ZA-1 are homogeneous and could be used as reference materials that would allow the expansion of calibration curves in XRF analysis up to 16000 μg g−1 for Rb, 2000 μg g−1 for Cs and 100 μg g−1 for Tl. STL-1 and ZA-1 also contain unusually high concentrations of Ga and Tl, and STL-1 of Nb.  相似文献   

15.
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16.
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   

17.
The contents of total carbon, hydrogen, nitrogen and sulfur in twenty-seven geological reference materials, issued by five producer organisations (USGS, CCRMP, ANRT, NIST and GSJ) were determined using an automated simultaneous elemental analyser following combustion. In order to complete gasification of C and N in some geological materials, the combustion temperature needed to be greater than 1150 °C. The calibrator prepared from known amounts of reagent material was not adopted for more than 1.2% m/m of H. Unrealistically high values in certain materials supposed to contain less than 1000 μg g−1 S may be due mainly to memory effects. The limit of detection was 50 μg g−1 for C and N, 500 μg g−1 for H and 1000 μg g−1 for S. Although the blank value of C and N was always stable and less than one third of the detection limit, it had a slightly higher value for N and S. By repeating long-term analysis, high reproducibility for each of the four elements was verified. The method has been applied satisfactorily to a variety of geological reference materials, and recommended values for C, H and N for most of the reference materials studied have been tabulated.  相似文献   

18.
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   

19.
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.  相似文献   

20.
A new technique for the in situ analysis of Re, Au, Pd, Pt and Rh in natural basalt glass by laser ablation (LA)-ICP-MS is described. The method involves external calibration against NIST SRM 612/613 or 614/615 glass certified reference materials, internal standardisation using Ca, and ablation with a 200 μm wide beam spot and a pulsed laser repetition rate of 50 Hz. Under these conditions, sensitivities for Re, Au, Pd, Pt and Rh analyte ions are ˜ 5000 to 100,000 cps/μg g-1. This is sufficient to make measurements precise to ˜ 10% at the 2-10 μg g-1 level, which is well within the range of concentrations expected in many basalts. For LA-ICP-MS calibration and a demonstration of the accuracy of the technique, concentrations of Re, Au, Pd, Pt and Rh in the NIST SRM 610/611 (˜ 1 to 50 μg g-1), 612/613 (˜ 1 to 7 μg g-1), 614/615 (˜ 0.2 to 2 μg g-1) and 616/617 (˜ 0.004 to 2 μg g-1) glasses were determined by solution-nebulisation (SN)-ICP-MS. Using the 612/613 or 614/615 glasses as calibration standards, LA-ICP-MS measurements of these elements in the other NIST glasses fell within ˜ 15% of those determined by SN-ICP-MS. Replicate LA-ICP-MS analyses of the 612/613 and 614/615 glasses indicate that, apart from certain anomalous domains, the glasses are homogeneous for Re, Au, Pd, Pt and Rh to better than 3.5%. Two LA-ICP-MS analyses of natural, island-arc basalt glasses exhibit large fractionations of Re, Au and Pd relative to Pt and Rh, compared to the relative abundances in the primitive mantle.  相似文献   

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